Copyright 2007-2010 Taina Maria Miller.
EDITION 1.4
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Please visit www.MathMammoth.com for more information about Maria Miller's math books. Create free math worksheets at www.HomeschoolMath.net/worksheets/
Contents
Foreword ... 5
Chapter 1: Getting Started Introduction ... 6
Some Review ... 8
Adding and Subtracting Within 0-100 ... 10
Ordinal Numbers ... 13
Fact Families ... 15
Dividing to Two Parts - Halves ... 17
Fourths and Other Parts ... 19
Chapter 2: Clock Introduction ... 21
Review - Whole and Half Hours ... 23
The Minutes ... 24
Five-Minute Intervals ... 27
How Much Time Passes? ... 31
Half and Quarter Hours ... 33
The Calendar ... 35
Review ... 37
Chapter 3: Addition and Subtraction Facts Within 0-18 Introduction ... 38
Review: Completing the Next Whole Ten ... 41
Review: Going Over Ten ... 43
Adding with 9 ... 45
Adding with 8 ... 47
Adding with 7 ... 49
Adding with 6 ... 51
Review - Facts with 6, 7, and 8 ... 52
Subtract to Ten ... 54
Subtraction and the Difference ... 56
Fact Families - 11 and 12 ... 60
Number Rainbows - 13 and 14 ... 62
Fact Families - 13 and 14 ... 63
Fact Families - 15 ... 66
Fact Families - 16 ... 68
Fact Families - 17 and 18 ... 70
Review ... 73
Chapter 4: Addition and Subtraction With Two-Digit Numbers Introduction ... 75
Adding with Whole Tens ... 78
Subtracting Whole Tens ... 81
Carrying to Tens ... 83
Going Over to the Next Ten ... 86
Two-Digit Numbers Ending in 9 ... 89
Add in Columns Practice ... 91
Two-Digit Numbers Ending in 8 or 7 ... 93
Addition Practice ... 95 Many Addends ... 97 Subtracting in Columns ... 100 Borrowing/Regrouping, Part 1 ... 101 Borrowing/Regrouping, Part 2 ... 104 Borrowing/Regrouping, Part 3 ... 107
Graphs and Problems ... 109
Mental Subtraction Methods ... 112
Euclid's Game ... 115
Mixed Review ... 118
Chapter 5: Counting Money Introduction ... 120
Counting Coins Review ... 122
Change ... 125
Dollars ... 128
Foreword
The Math Mammoth Grade 2-A and Grade 2-B worktexts comprise a complete math curriculum for the second grade mathematics studies.
The main topics during second grade, as in first grade, are the study of addition and subtraction and place value up to 1000.
In the second grade, children learn to add and subtract two and three-digit numbers mentally and in columns (under each other). They learn to carry to tens and to hundreds (also called regrouping), and how to borrow either from the tens or from the hundreds. The topics of borrowing two times and borrowing over zero tens are in this curriculum left for the third grade.
Mental math is very important, as it builds number sense and solidifies the understanding of place value. Children learn by heart the common addition and subtraction facts, and understand how to use them when adding two-digit numbers. They practice many kinds of mental math with three-digit numbers as well (in the 2B book).
Other topics studied are reading the clock to the five-minute intervals; measuring length, weight, and volume; shapes and a few simple geometry concepts; and money topics. These topics are important as well, since they are everyday applications of mathematics.
When you use these books as your only or main mathematics curriculum, they can be like a “framework”, but you still have liberty in planning your child's studies. While addition, subtraction, and place value topics are best studied in the order they are presented, you can choose to study clock, coins, and geometry topics in a different order. This does not totally apply to the chapter on measuring, as it uses 3-digit numbers.
Changing the topic might even be advisable if your child is “stuck” on some concept. Sometimes the brain mulls it over in the background, and the concept they were stuck on becomes clear after a break.
This curriculum aims to concentrate on a few major topics at a time and study them in depth. This is totally opposite to the continually spiraling step-by-step curricula, in which each lesson typically is about a different topic from the previous or next lesson, and includes a lot of review problems from past topics. This does not mean that your child wouldn't need an occasional review. However, when each major topic is presented in its own chapter, this gives you more freedom to plan the course of study and choose the review times yourself. In fact, I totally encourage you to plan your mathematics school year as a set of certain topics, instead of a certain book or certain pages from a book.
For review, I have included an html page called Make_extra_worksheets_grade2.htm that you can use to make additional worksheets for computation or for number charts. You can also always simply reprint some pages that were already studied .
I wish you success in your math teaching! Maria Miller, the author
Chapter 1: Getting Started
Introduction
The first chapter of the Math Mammoth Grade 2-A Complete Worktext has addition and subtraction review from the first grade, plus a few new topics that should be easy. The chapter starts out with review. Ordinal numbers are probably familiar from common language. The lesson Fact Families practices addition/subtraction connection, and introduces missing subtrahend problems such as __ − 5 = 4 where the total is missing. This is an early prelude to algebraic thinking.
The last two lessons introduce some easy parts, such as one-half, one-fourth, two-fourths and three-fourths. These lessons also practice finding half of a number or a fourth of a number. This is done for a good reason: First of all, the idea of finding part of a number is of paramount importance throughout elementary mathematics. Second, it prevents the fixation that half is “half of a pie” or that one-fourth is “one-fourth of a pie”, when halves and fourths apply to all kinds of “totals”. Third, the child will soon encounter the idea of a quarter of an hour when studying the clock, which is just one-fourth of an hour.
The Lessons in Chapter 1
Helpful Resources on the Internet
Use these free online resources to supplement the “bookwork” as you see fit. Number Cracker
Help Mr. Cracker obtain the secret code before the insidious Prof. Soup catches him by guessing what number comes next in a series of numbers.
http://www.funbrain.com/cracker/index.html Squigly
Squigly is hiding in one of the apples. Click on the ordinal number that tells the order of Squigly's apple. http://www.primarygames.com/squigly/start.htm
MathBlox
Click on two falling blocks that add up to the given number and they disappear. With various levels and number ranges.
http://www.iknowthat.com/com/L3?Area=Mathblox
page span (hours) Some Review ... 8 2 pages
Adding and Subtracting Within 0-100 ... 10 3 pages
Ordinal Numbers ... 13 2 pages
Fact Families ... 15 2 pages
Dividing to Two Parts - Halves ... 17 2 pages
Number Jump
Move the ball along the number line to smash the flies.
http://www.carstensstudios.com/mathdoodles/numberjump.htm Connect Sums
Click on the neighboring die-faces/numbers/coins so that the points add up to the given target sum. http://www.carstensstudios.com/mathdoodles/connectsums.html
Sum Stacker
Drag dies from stack to stack until the sums of each stack equal the sums given. http://www.carstensstudios.com/mathdoodles/sumsstacker.html
Some Review
1. The box with a “T” means a ten. Write the addition sentences.2. Add whole tens. You draw a ten-box, or some more ten-boxes to the picture.
3. Subtract from whole tens. One of the tens is shown with 10 dots, instead of a ten-box. Cover some of the dots to subtract.
4. Add in columns. The two numbers to be added are shown with dots and ten-boxes. a.
32
+7
=39
+ b. ____ + ____ = ____ + c. ____ + ____ = ____ + a. 25 + 10 = _____ 25 + 20 = _____ 25 + 30 = _____ + b. 14 + 10 = _____ 14 + 20 = _____ 14 + 30 = _____ + c. 32 + 10 = _____ 32 + 20 = _____ 32 + 30 = _____ + a. 60 – 3 = _____ 60 – 8 = _____ 60 – 7 = _____ b. 30 – 4 = _____ 30 – 6 = _____ 30 – 5 = _____ a. + b. +5. Cross out to subtract in (a) and (b). In (c) and (d), subtract in columns.
6. Add and subtract.
7. Solve the word problems.
a. 49 – 6 = _____ b. 47 – 16 = _____ c. 4 5 − 2 3 d. 9 8 − 6 5 a. 70 + 6 = _____ 50 + 9 = _____ b. 30 + 4 + 4 = _____ 50 + 7 + 2 = _____ c. 90 + ____ = 94 40 + ____ = 47 d. 60 + ____ = 90 40 + ____ = 80 e. 70 − 1 = _____ 100 − 5 = _____ f. 5 − 5 = ____ 24 − 4 = _____ g. 88 − 8 = _____ 57 − 7 = _____ h. 50 + ____ = 56 30 + ____ = 39
a. Luis bought two boxes of crayon for $6 each, and a stack of paper for $3.
What was his total cost?
b. Ernie has 7 marbles, and Jackie has 5. Jackie gives Ernie two of his.
How many more marbles does Ernie have now than Jackie?
c. Jack has twenty shirts, and ten of them are white. How many are not white?
d. A book costs $45. Can you buy it if you already have $22 and
Adding and Subtracting Within 0-100
1. Skip-count by fives, starting at 5.Color these numbers light blue.
2. Color yellow all the even numbers from 32 to 70. 3. What can the last digit of an even number be?
Even numbers end in ____, ____, ____, ____, or ____.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
4. Skip-count by tens starting at 17. Color these numbers pink.
What is similar about these numbers? They all end in ____.
5. Skip-count by tens backwards starting at 93. Color these numbers green.
What is similar about these numbers? They all end in ____.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
6. Color purple all the odd numbers from 89 to 51. 7. What can the last digit of an odd number be?
Odd numbers end in ____, ____, ____, ____, or ____. 8. Skip-count by fours starting at 4.
Color these numbers yellow.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
9. Skip-count. First find by which number to skip-count - by 2s, by 5s, or by 10s.
10. Write the addition sentences. The box with a “T” is a ten. Under each problem, there is another, similar, addition problem for you to solve. Can you see how it is similar?
11. Subtract by crossing some out. Under each problem, there is another, similar, problem.
12. Add and subtract. The problems in each box are similar.
a.
40, 42, 44, _____, _____, 50, _____, _____, _____, _____, _____
b._____, _____, _____, _____, 48, 58, 68, _____, 88, _____
c._____, _____, _____, _____, 65, 63, 61, _____, _____, _____
d._____, _____, _____, 70, 65, 60, _____, _____, _____, _____
+ a.____ + ____ = ____
b.34 + 3 = ____
c.____ + ____ = ____
d.53 + 6 = ____
+ e.____ + ____ = ____
f.32 + 5 = ____
+ a.59
–6 = _____
b.39
–6 = _____
c.47
–5 = _____
d.67
–5 = _____
e.60
–3 = _____
f.50
–3 = _____
a.2 + 6 = _____
42 + 6 = _____
72 + 6 = _____
b.4 + 4 = _____
74 + 4 = _____
94 + 4 = _____
c.3 + 6 = _____
53 + 6 = _____
23 + 3 = _____
d.8 + 2 = _____
48 + 2 = _____
98 + 2 = _____
e.7 – 5 = _____
37 – 5 = _____
67 – 5 = _____
f.9 – 4 = _____
29 – 4 = _____
99 – 4 = _____
g.10 – 4 = _____
50 – 4 = _____
80 – 4 = _____
h.8 – 5 = _____
38 – 5 = _____
88 – 5 = _____
13. Draw more dots so you complete the next whole ten. Write an addition sentence.
14. Complete the next whole ten. The problems in the bottom row are challenging!
+
a.13 + ___ = 20
+
b.____ + ___ = ____
+
c.____ + ___ = ____
a.32 + ___ = ____
b.74 + ___ = ____
c.48 + ___ = ____
d.42 + 3 + ____ = 50
e.37 + ____ + 1 = 40
f.84 + ____ + 4 = 90
15. Subtract the same number each time. a.– 10
50
52
64
23
____
____
____
____
b.
– 20
100
20
40
21
____
____
____
____
c.– 5
45
95
96
11
____
____
____
____
Find numbers for the boxes so that the sum of each row and of each column is a. 50 b. 80. a.
42
+
+
+
+
+
+
+
41
+
+
+
+
40
+
b.75
+
+
+
+
+
+
+
72
+
+
+
+
74
+
Ordinal Numbers
1. Circle.
The numbers 1, 2, 3, 4, and so on are called cardinal numbers.
But we also often use ordinal numbers. Ordinal numbers are used when talking about the order of things.
List of some ordinal numbers:
The fourth tree from the left is circled. It is also the second tree from the right.
The seventh letter of the word is S.
Ordinal Number Name
1st first 2nd second 3rd third 4th fourth 5th fifth 6th sixth 7th seventh 8th eighth
Ordinal Number Name
9th ninth 10th tenth 11th eleventh 12th twelfth 13th thirteenth 14th fourteenth 15th fifteenth 16th sixteenth
a. The second car from the left.
b. The fifth car from the right.
c. The seventh snowflake from the left.
d. The fourth snowflake from the right.
e. The ninth letter from the left.
f. The twelfth letter from the right.
2. Color.
3. Find the letters, and find out what Greg's surprise gift was.
a. The third flower from the left b. The first three flowers on the left
c. The fifth flower from the right. d. The first five flowers on the right.
The second row from the top,
the first letter from the left. ___
E S L A B G P B H E N I V S W N K P T L F J D A U D W M Y K Z N Y I C U D T S O Q R O T H A V E L
The fourth row from the top,
the third letter from the left. ___ The first row from the top,
the fifth letter from the right. ___ The fifth row from the bottom,
the second letter from the right. ___ The 1st row from the bottom,
the 1st letter from the left. ___ The sixth row from the top,
the third letter from the right. ___ The 3rd row from the top,
the 2nd letter from the left. ___ The 1st row from the top,
the 2nd letter from the left. ___
4. a. Choose the letters of the given word to make a new word.
S U R P R I S I N G
___ ___ ___ ___ ___
10th 5th 6th 9th 1st
b. Put the letters in the given order
to make a new word.
N D Y R T C I A I O
Fact Families
1. Write two addition and two subtraction sentences - a fact family!
2. Fill in the missing numbers. The four problems form a fact family. When you have two addition and
two subtraction facts that use the same numbers, it is called a “fact family”.
4 + 5 = 9 5 + 4 = 9
9 − 5 = 4
9 − 4 = 5
Notice the TOTAL. The subtraction sentences start with the total.
4 + 5 = 9
5 + 4 = 9
9 − 5 = 4
9 − 4 = 5 Notice the PARTS. The two parts make up the total.
Sometimes in a subtraction problem, the total is asked:
− 8 = 20
You know 20 and 8 are the “parts”, and the total is missing. To find the total, just add the “parts”: 20 + 8 = 28 a.
____ + ____ = ____
____ + ____ = ____
____ − ____ = ____
____ − ____ = ____
b.____ + ____ = ____
____ + ____ = ____
____ − ____ = ____
____ − ____ = ____
____ + ____ = ____
____ + ____ = ____
____ − ____ = ____
____ − ____ = ____
c. a.2 +
= 8
+ 2 = 8
8 − 2 =
8 −
= 2
b.____ + ____ = 10
____ + ____ = 10
10 − 7 =
10 −
= 7
c.____ + ____ = ____
____ + ____ = ____
9 −
= 6
____ − ____ = ____
3. Write a matching addition sentence for the subtraction sentence. There are two possibilities.
4. The total is missing from the subtraction sentence. Solve.
5. Find the missing numbers.
a.
____ + ____ = ____
8 − 2 = 6
b.____ + ____ = ____
20 − 7 = 13
c.____ + ____ = ____
60 − 20 = 40
When the first number is missing in a subtraction, it is the TOTAL that is missing. You can find the TOTAL by adding
the two numbers (those are the “parts”).
– 6 = 2
The total is missing. 6 and 2 are the “parts”. So we add them.
2 + 6 = 8. The missing number is 8!
It's like “adding backwards”:
a.
– 5 = 4
b.– 7 = 2
c.– 7 = 10
a.– 2 = 4
– 50 = 50
– 8 = 20
b.– 7 = 80
60 + 4 =
16 +
= 20
c.9 –
= 5
77 +
= 78
– 9 = 60
Find the missing numbers. This time adding backwards will NOT work!
a. 50 − = 10 33 − = 31 b. 100 − = 91 76 − = 72 c. 10 − − 2 = 1 9 − − 5 = 2
Dividing into Two Parts — Halves
2. Draw a line through these shapes and divide them into two halves. Color one half.
3. Divide the items into two EQUAL groups. Write an addition sentence. Find half of the total. If you divide something into two of the same size parts, or
two equal parts, then either part is one-HALF of the whole.
You can also write one-half this way: 1/2
You can also find half of so-many objects. For example, you can find half of ten apples. It is five apples.
You can also find half of a number. For example, half of 6 is 3. We write one-half this way: 1
2
1. a. Color one half of each shape. b. Color two halves of each shape.
a. b. c. d. e. 10 balls a. ____ + ____ = _____ 1 2 of 10 is ____. 40 b. ____ + ____ = _____ 1 2 of 40 is ____. 24 c. ____ + ____ = _____ 1 2 of 24 is ____.
4. Remember your doubles? Fill in the chart.
5. Divide the items into two EQUAL groups. Write an addition sentence. Find half of the total.
6. Solve the word problems, and fill in another chart of doubles and halves to help you.
e. The recipe called for 10 apples. That was exactly half of Mom's apples. How many apples had mom bought originally?
1 + 1 = ____ 2 + 2 = ____ 3 + 3 = ____ 4 + 4 = ____ 5 + 5 = ____ 1 2 of 2 is 1 . 1 2 of 4 is 2 . 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____. 6 + 6 = ____ 7 + 7 = ____ 8 + 8 = ____ 9 + 9 = ____ 10 + 10 = ____ 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____. a. ____ + ____ = _____ 1 2 of ___ is ____. b. ____ + ____ = _____ 1 2 of ___ is ____. c. ____ + ____ = _____ 1 2 of ___ is ____.
a. Jack and Joe split $60 between them. How many dollars did each get? b. What is half of 60 minutes? c. Half of 100 students were sick. How many were not sick?
d. Aunt Katie gave Missie half of $40. Missie spent $10 on a toy.
How many dollars does Missie have now?
10 + 10 = _____ 20 + 20 = _____ 30 + 30 = _____ 40 + 40 = _____ 50 + 50 = _____ 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____. 1 2 of ___ is ____.
Fourths and Other Parts
1. Color the part indicated.
1 4
A square is divided into four equal parts. One part is colored.
We also write one-fourth as 1/4. If you need to find 1/4 of any thing, first divide it into four equal groups. The colored part is one-fourth: 1
4 1 4 of the circle 1 4 of the stars 1 4 of the rectangle 1 4 of the hearts 1 4 2 4 3 4 4 4
one-fourth two-fourths three-fourths four-fourths
a. 1 2 b. 1 4 c. 3 4 d. 2 2 e. 2 4 f. 1 2 g. 3 4 h. 4 4 i. 1 4 j. 1 2
2. Divide these items into four EQUAL groups. Find one-fourth of the total. 8 balls a. 1 4 of 8 is ____. 12 balls b. 1 4 of 12 is ____. 40 c. 1 4 of 40 is ____. 16 d. 1 4 of 16 is ____.
3. a. Here you see 100 little squares.
Color 1/4 of them.
1
4 of 100 is _____.
b. Here you see 60 little squares.
Color 1/4 of them.
1
4 of 60 is _____.
c. Here you see 80 little squares.
Color 3/4 of them.
3
4 of 80 is _____.
4. Remember the quarter coin? The word “quarter” means one-fourth. Four quarters makes one dollar, or 100 cents.
4 quarters = 1 dollar
=
1 dollar = 100 pennies
1
4 of 100 cents is _____ cents = 1 quarter. 1
2 of 100 cents is _____ cents = 2 quarters. 3
Chapter 2: Clock
Introduction
The second chapter of the Math Mammoth Grade 2-A Complete Worktext deals with reading the clock to the five-minute intervals, and finding simple time intervals.
It is helpful to have a practice clock, such as an alarm clock, where the child can turn the clock hands. First we practice telling time in the hours:minutes form (such as 10:20), and then using the colloquial phrases “ten after”, “quarter till”, and so on.
Also studied are simple time intervals, or how much time passes. When practicing these, tell the child to imagine moving the minute (or hour) hand on a clock. He/she can initially use a practice clock for this. The section also has one lesson about the calendar. Of course the calendar and the months are best learned just in the context of everyday life, as the months pass. Hang a wall calendar on the wall and instruct your child to look at it every day, and to cross out days as they pass.
The Lessons in Chapter 2
Helpful Resources on the Internet
Use these free online resources to supplement the “bookwork” as you see fit. Analog and Digital Clocks
These clocks show you the current time, side by side. Useful for illustration. http://nlvm.usu.edu/en/nav/frames_asid_316_g_2_t_4.html
What Time Will it Be?
Move the hands on the clock to show what time it will be after a certain amount of minutes. http://nlvm.usu.edu/en/nav/frames_asid_318_g_2_t_4.html
Match Clocks
Make the digital clock to show the time given with the analog clock. http://nlvm.usu.edu/en/nav/frames_asid_317_g_2_t_4.html
page span Review - Whole and Half Hours ... 23 1 page The Minutes ... 24 3 pages Five Minute Intervals ... 27 4 pages How Much Time Passes? ... 31 2 pages Half and Quarter Hours ... 33 2 pages The Calendar ... 35 2 pages Review ... 37 1 page
Time Flies
Practice telling time with two types of watches. In the second part, practice what you have learned by selecting the digital time that matches the time displayed.
http://www.alfy.com/Games/playgame.aspx?gameID=354&gameName=Time+Flies Flashcard Clock
Read the analog and type in the time in digital form. Very clear clock and good fast response! http://www.teachingtreasures.com.au/maths/FlashcardClock/flashcard_clock.htm
Telling Time Practice
Interactive online practice: you drag the hands of the clock to show the correct time. http://www.worsleyschool.net/socialarts/telling/time.html
Teaching Time
Analogue/digital clock games and worksheets. Also an interactive “class clock” to demonstrate time. http://www.teachingtime.co.uk/
Time-for-time
Resource site to learn about time: worksheets, games, quizzes, time zones. http://www.time-for-time.com/default.htm
A Matter of Time
Lesson plans for telling time, interactive activities, and some materials to print. http://www.fi.edu/time/Journey/JustInTime/contents.html
Elapsed Time Line
This interactive tool shows 2 clocks that have draggable fingers to set a "from" and "to" time, and a number line. You can demonstrate how to use a number line to calculate elapsed time.
www.teacherled.com/2008/10/05/elapsed-time-line/ Clockwise
Plug in a time, and the clock runs till it, or clock runs to a time and you type it in. http://www.shodor.org/interactivate/activities/clock2/index.html
Clock (evaluation version words across the screen)
Use the buttons to advance the clock in 5, 10, 15, 30 minute increments or drag the hands. Shows digital time also. For illustrations only, does not have any quiz or questions.
http://www.interactive-resources.co.uk/mathspack1/clock/clock.html The Right Time
A couple of interactive exercises about reading the clock. http://www.pitara.com/activities/math/time/time.asp?QNum=3 What Time Is It?
Look at the analog clock and pick the digital clock that shows the same time. http://www.primarygames.com/time/start.htm
Review - Whole and Half Hours
1. Write or say the time using the expressions o'clock or half past.2. Write the time in two ways: using the expressions o'clock or half past, and with numbers.
3. Write the time an hour later. Use numbers.
4. Write the time a half-hour later. Use numbers.
a. b. c. d. a. _____ o'clock _____ : _____ b. half past _____ _____ : _____ c. half past _____ _____ : _____ d. _____ o'clock _____ : _____ Now it is: a. 6:00 b. 11:30 c. 3:00 d. 2:30 e. 9:30
An hour later, it is:
Now it is: a. 5:00 b. 7:30 c. 12:30 d. 10:00 e. 1:30
The Minutes
1. The arrow shows how much the minute hand travels. How many minutes of time passes? When the hour hand moves from one number to the next (from
1 to 2, or from 6 to 7, etc.), it takes one hour to do that. In that same one hour of time, the minute hand travels
from 0 to 60 minutes. So one hour is 60 minutes. A half-hour
is 30 minutes.
When you read the minute hand, you use the green numbers. They go by fives, and are not normally marked on clocks. You need to know them. (Just skip-count by fives!)
1 hour = 60 minutes. 1/2 hour = 30 minutes.
The hour hand is past 8. The minute hand is at 15. The time is 8:15.
The hour hand is past 3. The minute hand is at 25. The time is 3:25.
The hour hand is past 11. The minute hand is at 10. The time is 11:10.
2. Write the time.
3. Find the clock that shows 11:25 and the clock that shows 11:05.
4. Write the time that the clock shows, and the time 5 minutes later.
a. ____ : _____ b. ____ : _____ c. ____ : _____ d. ____ : _____ e. ____ : _____ f. ____ : _____ g. ____ : _____ h. ____ : _____ a. b. c. d. a. ____ : _____ b. ____ : _____ c. ____ : _____ d. ____ : _____ 5 min. later → ____ : _____ ____ : _____ ____ : _____ ____ : _____
5. Write the time. Note: the hour hand is close to some number, but it has not reached that yet.
6. Write the time that the clock shows, and the time 5 minutes later.
Notice! The hour hand looks like it is pointing to 10.
But the minute hand has not yet reached 60 minutes, so it is not yet 10 o'clock. We still say it is 9 hours (and some minutes).
The minute hand is at 55. The time is 9:55.
a. ____ : _____ b. ____ : _____ c. ____ : _____ d. ____ : _____
e. ____ : _____ f. ____ : _____ g. ____ : _____ h. ____ : _____
a. ____ : _____ b. ____ : _____ c. ____ : _____ d. ____ : _____
5 min.
Five-Minute Intervals
1. Continue writing the times at each five-minute interval. You can use your practice clock. When the MINUTE hand travels from
one number to the next on the clock face, 5 minutes of time passes.
Each interval is five minutes. That is why you skip-count by fives, when figuring out the minutes.
a. b. c. d. 8 : 20 8 : 25 _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____ _____ : _____
2. How many minutes is it past the whole hour, or till the next whole hour? We can also tell the time by
saying how many minutes it is past the whole hour, or how many minutes it is till the next whole hour.
Use the expression “so-many minutes past” only if the minutes are less than 30. After that, use “so-many minutes till” the next whole hour.
20 past 1
“20 minutes past 1 o'clock”.
10 till 7
“10 minutes till 7 o'clock.”
a. It is ____ minutes past 2 o'clock. b. It is ____ minutes past 3 o'clock. c. It is ____ minutes past ____ o'clock. d. It is ____ minutes past _____ o'clock. e. It is ____ minutes till 7 o'clock. f. It is ____ minutes till ____ o'clock. g. It is ____ minutes till ____ o'clock. h. It is ____ minutes till ____ o'clock.
i. ____ past ___ j. ____ past ___ k. ____ past ___ l. ____ past ___
3. Write the time using the wordings “past”, “till”, “half past” or “o'clock”, and the time 5 minutes later.
4. Write the time using the hours:minutes way. Use your practice clock to help.
a. ____ till ___ b. ____ till ___ c. ____ past ___ d. ____ past ___
5 min.
later → ____ till ___ ____ till ___ ____ past ___ ____ past ___
e. f. g. h. 5 min. later → i. j. k. l. 5 min. later → a. 10 past 8 ______:______ b. 15 till 7 ______:______ c. 25 past 12 ______:______ d. half-past 7 ______:______ e. 9 o'clock ______:______ f. 20 till 6 ______:______ g. 5 till 11 ______:______ h. 25 till 4 ______:______
5. Write the time using the expressions “past”, “till”, or “half past”.
6. How many minutes does the minute hand “cover”, or “pass through”, on the clock?
7. Write the later times.
a. 6:45 b. 9:30 c. 12:10 d. 4:55 e. 8:35 f. 1:40 g. 2:15 h. 11:50 a. From 10:00 till 10:15 ______ minutes b. From 1:20 till 1:35 ______ minutes c. From 5:50 till 6:10 ______ minutes d. From 2:05 till 2:40 ______ minutes a. z 15 min. later ____:_____ z 20 min. later ____:_____ z 30 min. later ____:_____ b. z 15 min. later ____:_____ z 20 min. later ____:_____ z 30 min. later ____:_____ c. z 15 min. later ____:_____ z 20 min. later ____:_____ z 30 min. later ____:_____ d. z 15 min. later ____:_____ z 20 min. later ____:_____ z 30 min. later ____:_____ e. z 15 min. later ____:_____ z 20 min. later ____:_____ z 30 min. later ____:_____ f. z 15 min. later ____:_____ z 20 min. later ____:_____ z 30 min. later ____:_____
How Much Time Passes?
1. How many minutes till 2:30? Till 8:05?2. The class ends at 1:00. How many minutes of class is left at these times?
3. How many minutes pass? Imagine turning the minute hand on a clock.
4. a. The bus trip started at 10 past 4, and ended at half past 4. How many minutes did it take? b. Joshua started math homework at 20 till 5, and ended at 5 past 5.
How much time did he spend?
c. Music class starts at 10:15, and ends at 10:45. How long is it? a. It is 2:00. → ______ minutes till It is 2:10. → ______ minutes till It is 2:20. → ______ minutes till It is 2:25. → ______ minutes till 2:30 b. It is 7:30. → ______ minutes till It is 7:35. → ______ minutes till It is 7:45. → ______ minutes till It is 7:50. → ______ minutes till 8:05 a. _______ minutes b. _______ minutes c. _______ minutes d. _______ minutes from 1:45 1:55 1:40 1:45 1:55 to 1:55 2:05 2:05 2:15 2:10 minutes 10 minutes from 2:00 7:05 8:45 6:40 11:15 to 2:35 7:15 9:05 7:10 11:30 minutes
5. How many hours is it?
6. How many hours till midnight?
7. a. Dad's workday starts at 8:00 in the morning, and ends at 5 PM. How many hours is Dad at work?
b. Mary's school day starts at 9 AM and ends at 2 PM. How long is her school day? c. The airplane took off at 10 AM and landed at 1 PM. Then it again took off again at 2 PM and landed at 6 PM. How many hours was the airplane in the air?
d. How many hours are there in 1 day-night period?
8. a. The turkey needs to cook 3 hours in the oven to be ready at 7 PM. When should it be put into the oven?
b. It takes 2 hours to mow the lawn. Jim wants to be done at 1 PM. When should he start mowing?
c. Mom needs 7 hours of sleep tonight. She wants to wake up at 6 AM. When should she go to bed?
9. Imagine the minute hand going all the way around on the clock - or full hours. Fill in how many whole hours pass.
from 8 AM 7 AM 9 AM 11 AM 10 AM
to 12 noon 1 PM 4 PM 11 PM 7 PM
hours
from 4 PM 7 PM 12 AM 9 AM 7 AM
to 12 midnight 12 midnight 12 midnight 12 midnight 12 midnight
hours
from 10:30 10:30 1:40 5:45 3:20 AM
to 11:30 12:30 4:40 11:45 12:20 PM
full rounds or hours
Half and Quarter Hours
1. Write the time using “a quarter past”, “a quarter till”, “half past”, or “o'clock”. The clock face is divided into four equal parts.
Each part is one-fourth.
We can see that one-fourth of 60 minutes is 15 minutes. The word “quarter” means one-fourth.
When we say, “A quarter past 6”, we mean one-fourth of an hour past 6 o'clock, or 15 minutes past 6.
When we say, “A quarter till 6”, we mean one-fourth of an hour till 6 o'clock, or 15 minutes till 6.
When we say, “Half-past 6”, we mean a half-hour past 6 o'clock, or 30 minutes past 6.
1 hour = 60 minutes. 1/2 hour = 30 minutes. 1/4 hour = 15 minutes.
15 past 4, OR a quarter past 4 15 till 8, OR a quarter till 8 half past 10
a. b. c. d.
2. Write the times using hours:minutes.
3. Write the time using “a quarter past”, “a quarter till”, “half past”, or “o'clock”.
4. Which clock shows the time a half-hour later than the given time?
5. a. Mom started cooking rice at a quarter past 5. It needs to cook for 30 minutes. When will it be ready?
b. A rain storm lasted half an hour, starting at a quarter till 2. When did it end? c. The class ends at 2 o'clock. Now there are still 15 minutes left of class time. What time is it now?
a. a quarter till 5 _____ : ______ b. a quarter past 12 _____ : ______ c. a quarter till 9 _____ : ______ d. a quarter past 3 _____ : ______ e. half past 11 _____ : ______ f. a quarter till 12 _____ : ______ g. a quarter past 8 _____ : ______ h. a quarter till 1 _____ : ______ a. 7:30 b. 5:15 c. 5:45 d. 9:45 e. 12:15 f. 12:30 g. 11:45 h. 7:45 a.a quarter past 5 b. half past 4 c. 3 o'clock d. a quarter till 6 e.a quarter till 7 f. a quarter past 4 1. 2. 3. 4. 5. 6.
The Calendar
Discuss with your teacher:
1. What do the letters “Su Mo Tu We Th Fr Sa“ mean? 2. (Use the calendar above.) What day of the week is...
January Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 February Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 March Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 April Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 May Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 June Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 July Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 August Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 September Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 October Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 November Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 December Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
a. April 4th b. October 13th c. December 3rd
d. May 28th e. September 1st f. February 19th
3. a. List here all the months that have 31 days.
b. List here all the months that have 30 days.
c. Which month is the shortest month? ________________________ How many days does it have? ____
4. Write the dates, using the form (month) (day), like in problem (2). The day number is an ordinal number!
5. Write the date exactly one week (7 days) later than these dates:
6. a. Let's say it is now April first. How many months is it till June? Till August? Till December? Till October?
b. Let's say it is now January first. How many months is it till February? Till April? Till July? Till September?
7. If you have already had your birthday for this year, how many months ago was it? If you haven't had it yet, how many months is it from today until your birthday? 8. Mary goes to a swimming club every Thursday. List here the May dates when Mary goes swimming.
9. Jack ordered a passport on July 3rd. He is supposed to pick it up two weeks later. What date is that?
a. today's date b. tomorrow's date
c. your birthday d. your mom's birthday
e. Monday next week f. the first Monday of June
a. January 3rd b. February 11th
c. May 22nd d. June 5th
e. August 30th f. November 26th
Review - Clock to the Nearest Five Minutes
1. Write the time with hours:minutes, and using “past”, “till”, “half past” or “o'clock”.
2. Write the later time.
3. How many minutes pass? Imagine turning the minute hand on a clock.
4. How many hours is it? a. ____ : ______ _____ till ____ b. ____ : ______ _____ past ____ c. ____ : ______ ________________ d. ____ : ______ ________________ e. ____ : ______ _____ till ____ f. ____ : ______ ________________ g. ____ : ______ ________________ h. ____ : ______ ________________ Time now 2:30 6:55 15 min. later ____ : _____ ____ : _____ Time now 9:05 5:40 20 min. later ____ : _____ ____ : _____ from 1:45 1:55 1:40 1:45 1:55 to 1:55 2:05 2:05 2:15 2:10 minutes 10 minutes from 8 AM 7 AM 9 AM 11 AM 10 AM to 12 noon 1 PM 4 PM 11 PM 7 PM hours
Chapter 3: Addition and Subtraction Facts Within 0-18
Introduction
The third chapter of the Math Mammoth Grade 2-A Complete Worktext provides lots of practice for learning and memorizing the basic addition facts of single-digit numbers where the answer is between 10 and 18, and learning to use them with subtraction.
Completing the ten - concept
This concept is important to learn. The child learns what number is needed to complete the next whole ten. For example, what number do you add to 23 to get 30, or 23 + __ = 30. The next step is to study what happens when the sum goes over the next ten.
In the lesson “Going Over Ten”, the child learns to add 8 + 5 by first adding 8 + 2 (which completes the ten) and then the “leftover” 3. These prepare the child for addition facts where the sum is more than 10.
Memorizing the facts
The National Council of Teachers of Mathematics (NCTM) recommends in their Grade 2 Curriculum Focal Points that children “...develop quick recall of basic addition facts and related subtraction facts”. Mathematics builds upon previously learned concepts and facts. Learning addition and subtraction facts is essential for later study. For example, the child will soon study double-digit addition and subtraction, and needs to be able to add and subtract small numbers efficiently.
The next lessons in the book provide lots of practice for learning and memorizing the addition facts. There are 20 such facts:
9 + 2 till 9 + 9: 8 facts 8 + 3 till 8 + 8: 6 facts 7 + 4 till 7 + 7: 4 facts 6 + 5 till 6 + 6: 2 facts
After those lessons, we reverse the process and practice subtracting. First, the child subtracts TO ten with problems such as 16 − __ = 10. Then come subtraction problems which “cross” the ten the other direction, such as 16 − 7. Again the student first practices these by subtracting in two parts: First subtracting to ten, then the rest. For example, 16 − 7 becomes 16 − 6 − 1.
The various lessons about the fact families give lots of practice and further reinforce memorizing the facts. These lessons also include many word problems. You can choose to skip some of these lessons or problems, or use them later for review. They do not contain any new concepts.
Alongside this book, you can also use math games or flashcards to reinforce the addition and subtraction facts. You can find a list of some free online games at
www.homeschoolmath.net/math_resources_2.php
The Lessons in Chapter 3
Helpful Resources on the Internet
Use these free online resources to supplement the “bookwork” as you see fit. Space Jumps
Adding two single-digit numbers, first jump to ten, then the rest to the spaceship. Practices addition that goes over ten.
http://www.ictgames.com/spacejumps.html Bridging Shuttle
Bridging Through Ten means the same as adding to ten first, then the rest. Get a “flight plan”, then first add to ten by typing the number needed into the oval, and press the red button. Then type the rest that the shuttle needs to go, into the other oval, and press the red button.
http://www.ictgames.com/bridging.html Speedy Sums
Click on numbers that add to the target sum. The more numbers you use, the higher your score will be. http://www.mathplayground.com/speedy_sums.html
page span Review: Completing the Next Whole Ten ... 41 2 pages Review: Going Over Ten ... 43 2 pages Adding with 9 ... 45 2 pages Adding with 8 ... 47 2 pages Adding with 7 ... 49 2 pages Adding with 6 ... 51 1 page Review - Facts with 6, 7, and 8 ... 52 2 pages Subtract to Ten ... 54 4 pages Subtraction and the Difference ... 56 2 pages Number Rainbows- 11 and 2 ... 58 2 pages Fact Families - 11 and 12 ... 60 2 pages Number Rainbows - 13 and 14 ... 62 1 page Fact Families - 13 and 14 ... 63 3 pages Fact Families - 15 ... 66 2 pages Fact Families - 16 ... 68 2 pages Fact Families - 17 and 18 ... 70 3 pages Review ... 73 2 pages
Math Magician Games
Flashcard problems in all 4 operations, including subtraction. Answer 20 questions in 1 minute. http://www.oswego.org/ocsd-web/games/Mathmagician/mathssub.html
AplusMath Games
Matho (math and bingo combined), concentration, hidden picture, and Planet Blaster games for the basic operations.
http://www.aplusmath.com/games/ Addition Surprise
Draw the answer square in the addition table. http://www.hbschool.com/activity/add/add.html Exuberant Eye Games
Practice your basic facts with these kid-appealing simple games. http://www.games.exuberanteye.com/
Power Lines Puzzle
Arrange the numbers into the pattern so that the numbers on the “lines” add up to the given sum. http://www.primarygames.co.uk/pg2/powerlines/powerlines1.html
Online Addition Flashcards
http://www.thegreatmartinicompany.com/additionfill.html Number Bond Machines
Practice which two numbers add up to a given number. Set the number to be 11, 12, ... 18 to practice basic facts as in this chapter.
http://www.amblesideprimary.com/ambleweb/mentalmaths/numberbond.html
Review: Completing the Next Whole Ten
1. Write the previous and next whole ten. Circle the ten that is nearer the number.2. Write the previous and next whole tens. Below, write the two differences: the difference
between the previous whole ten and the number, and the difference between the number and the next whole ten. See the example.
3. Complete the next ten. Below, write the same kind of problem within numbers 0-10.
4. Complete the next ten. Think of the corresponding problem within the range of 0-10. a.
____, 56, ____
____, 37, ____
b.____, 72, ____
____, 25, ____
c.____, 94, ____
____, 31, ____
Differences: a.60 , 63 , 570
3 7
b._____ , 46 , _____
____ ____
c._____ , 95 , _____
____ ____
Differences: d._____ , 72 , _____
____ ____
e._____ , 41 , _____
____ ____
f._____ , 44 , _____
____ ____
a.17 + ____ = 20
7 + ____ = 10
b.62 + ____ = ____
2 + ____ = ____
c.94 + ____ = ____
4 + ____ = ____
a.42 + ____ = 50
55 + ____ = ____ 61 + ____ = ____ b.22 + ____ = ____
97 + ____ = ____
34 + ____ = ____
c.66 + ____ = ____
32 + ____ = ____
83 + ____ = ____
5. Fill in the missing numbers. Compare the top and bottom problems!
6. Find your way through the maze! Start at the top. You can only go on a square where the sum is a whole ten.
7. Complete the next whole ten.
8. Find as many different sums as you can to make one hundred! a.
73 + ____ = 80
73 + ____ = 81
b.35 + ____ = 40
35 + ____ = 41
c.14 + ____ = 20
14 + ____ = 21
13 + 6 54 + 6 73 + 8 45 + 7 99 + 4 15 + 9 14 + 8 15 + 5 13 + 6 32 + 7 45 + 7 73 + 7 64 + 5 82 + 9 16 + 7 30 + 12 39 + 1 74 + 6 73 + 9 52 + 7 46 + 7 32 + 7 31 + 9 86 + 4 65 + 4 92 + 4 21 + 8 24 + 7 22 + 8 32 + 6 83 + 6 11 + 7 98 + 2 57 + 3 17 + 9 44 + 9 12 + 8 95 + 6 38 + 5 53 + 9 71 + 9 34 + 4 36 + 7 19 + 4 28 + 11 53 + 7 29 + 2 26 + 6 78 + 6 32 + 5 a.17 + ____ + 1 = 20
12 + ____ + 4 = 20
13 + ____ + 4 = 20
b.35 + ____ + 2 = 40
32 + ____ + 3 = 40
36 + ____ + 3 = 40
c.41 + ____ + 6 = 50
44 + ____ + 3 = 50
42 + ____ + 5 = 50
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
90 + ____ + ____ = 100
Review: Going Over Ten
1. Circle all the blue balls and some of the red ones so that you get a ten. Then add the rest of the red balls.
2. Write a number on the empty line that completes ten. Then add the last number.
Sums that go over 10
Let's add 8 + 6 so that we first make a ten. 8 + 6
| \ 8 + 2 + 4 10 + 4 = 14
The 6 is broken into two parts: 2 and 4. That is because 8 and 2 make a ten.
Then, we have 10 and 4. We get 14.
Let's add 9 + 7 so that we first make a ten. 9 + 7
| \ 9 + 1 + 6 10 + 6 = 16
The 7 is broken into two parts: 1 and 6. That is because 9 and 1 make a ten.
Then, we have 10 and 6. We get 16.
a. 8 + 4 10 + 2 = ____ b. 9 + 5 10 + ____ = ____ c. 8 + 6 10 + ____ = ____ d. 9 + 3 10 + ____ = ____ e. 7 + 5 10 + ____ = ____ f. 9 + 8 10 + ____ = ____ a. ( 7 + 3 ) + 2 = b. ( 5 + ___ ) + 3 = c. ( 8 + ___ ) + 4 = d. ( 6 + ___ ) + 4 = e. ( 9 + ___ ) + 7 = f. ( 7 + ___ ) + 5 =
3. Complete. Break the second number into two parts so that you get a ten.
4. Add up to 10, 11, 12 and notice the patterns!
6. Solve the word problems.
a. 8 + 7 / \ 8 + 2 + ____ 10 + ____ = ____ b. 8 + 9 / \ 8 + 2 + ____ 10 + ____ = ____ c. 8 + 5 / \ 8 + 2 + ____ 10 + ____ = ____ d. 9 + 4 / \ 9 + 1 + ____ 10 + ____ = ____ e. 9 + 6 / \ 9 + ___ + ____ 10 + ____ = ____ f. 9 + 9 / \ 9 + ___ + ____ 10 + ____ = ____ a.
8 + ___ = 10
8 + ___ = 11
8 + ___ = 12
b.7 + ___ = 10
7 + ___ = 11
7 + ___ = 12
c.9 + ___ = 10
9 + ___ = 11
9 + ___ = 12
d.6 + ___ = 10
6 + ___ = 11
6 + ___ = 12
5. Circle the even numbers.
15 24 58 89 99
40 51 67 100 2
a. You have $8 and you buy a toy for $5 and candy for $2.
How much money do you have now?
b. Cassie had $8. Then she found $5 in her piggy
bank, and her mom gave her $2.
How much money does she have now?
c. Matthew had $8. He spend $3 on a bottle of juice.
Later he found $2 on the street.
Adding with 9
2. It is good to memorize the doubles, also. Fill in.
Imagine that 9 really wants to be a 10! It takes one from the other number (from 5). So, 9 becomes 10, and 4 are left over.
+ = =
9 + 5 = 10 + 4 = 14
9 wants to be a 10! So, it takes one from the other number (from 3). So, 9 becomes 10, and 2 are left over.
+ = =
9 + 3 = 10 + 2 = 12
Use the list on the right to practice. Don't write the answers there. Just point to different problems and say the answer aloud.
1. Add. First encircle the ten.
a. 9 + 5 10 + 4 = ____ b. 9 + 4 10 + ____ = ____ c. 9 + 7 10 + ____ = ____ d. 9 + ___ 10 + ____ = ____ e. 9 + ___ 10 + ____ = ____ f. 9 + ___ 10 + ____ = ____ 9 + 1 = 9 + 2 = 9 + 3 = 9 + 4 = 9 + 5 = 9 + 6 = 9 + 7 = 9 + 8 = 9 + 9 = 2 + 2 = ____ 3 + 3 = ____ 4 + 4 = ____ 5 + 5 = ____ 6 + 6 = ____ 7 + 7 = ____ 8 + 8 = ____ 9 + 9 = ____ 10 + 10 = ____
3. Add to nine. Think how 9 wants to be a ten, and takes 1 from the other number.
4. Here are addition facts with nine. Do not write the answers down, but just practice the sums.
5. Add. Remember, you can add both ways. For example, 7 + 9 = 9 + 7.
6. What is missing? a. 9 + 6 10 + 5 = ____ b. 9 + 8 10 + ____ = ____ c. 9 + 5 10 + ____ = ____ d. 9 + 2 10 + ____ = ____ e. 9 + 7 10 + 6 = ____ f. 9 + 9 10 + ____ = ____ g. 9 + 8 10 + ____ = ____ h. 9 + 3 10 + ____ = ____ 9 + 0 = 9 + 3 = 9 + 7 = 9 + 5 = 9 + 6 = 9 + 8 = 9 + 9 = 9 + 1 = 9 + 2 = 9 + 4 = 9 + 10 = a. 9 + 4 = ____ 8 + 9 = ____ 9 + 5 = ____ b. 9 + 7 = ____ 4 + 9 = ____ 9 + 4 = ____ c. 3 + 9 = ____ 9 + 2 = ____ 9 + 9 = ____ d. 5 + 9 = ____ 8 + 9 = ____ 9 + 6 = ____ a. 9 + ____ = 13 9 + ____ = 15 b. 9 + ____ = 16 9 + ____ = 14 c. 9 + ____ = 17 9 + ____ = 11 d. 9 + ____ = 12 9 + ____ = 18
You can use this same "trick" with 19, 29, 39, 49, and so on. Imagine that 49 really wants to be 50, and so it "steals" 1 from the other number. Solve.
a. 49 + 7 = _____ 19 + 6 = _____ b. 59 + 5 = _____ 89 + 9 = _____ c. 69 + 3 = _____ 29 + 6 = _____
Adding with 8
2. It is good to memorize the doubles, also. Fill in.
Imagine that 8 wants to be a 10! It takes two from the other number (from 3). So, 8 becomes 10, and only 1 is left over.
+ = =
8 + 3 = 10 + 1 = 11
8 wants to be a 10! So, it takes two from the other number (from 5). So, 8 becomes 10, and 3 are left over.
+ = =
8 + 5 = 10 + 3 = 13
Use the list on the right to practice. Don't write the answers there. Just point to different problems and say the answer aloud.
1. Add. First, circle the ten.
a. 8 + 5 10 + 3 = ____ b. 8 + 4 10 + ____ = ____ c. 8 + ____ 10 + ____ = ____ d. 8 + ____ = 10 + ____ = ____ e. 8 + ____ = 10 + ____ = ____ f. 8 + ____ = 10 + ____ = ____ 8 + 1 = 8 + 2 = 8 + 3 = 8 + 4 = 8 + 5 = 8 + 6 = 8 + 7 = 8 + 8 = 8 + 9 = 2 + 2 = ____ 3 + 3 = ____ 4 + 4 = ____ 5 + 5 = ____ 6 + 6 = ____ 7 + 7 = ____ 8 + 8 = ____ 9 + 9 = ____ 10 + 10 = ____
Here are addition facts with eight. Do not write the answers down, but just practice the sums.
3. Add and fill in what is missing.
4. Find the pattern and continue it.
8 + 0 = 8 + 3 = 8 + 10 = 8 + 5 = 8 + 7 = 8 + 1 = 8 + 8 = 8 + 1 = 8 + 6 = 8 + 9 = 8 + 4 = 8 + 2 = a. 8 + 4 = ____ 8 + 6 = ____ 8 + 2 = ____ b. 8 + 8 = ____ 8 + 5 = ____ 8 + 7 = ____ c. 8 + ____ = 14 8 + ____ = 16 8 + ____ = 17 d. 8 + ____ = 13 8 + ____ = 12 8 + ____ = 11 e. 5 + 8 = ____ 8 + 7 = ____ 3 + 8 = ____ f. 6 + 8 = ____ 8 + 9 = ____ 8 + 8 = ____ a. 8 + 2 = ____ 8 + 4 = ____ 8 + 6 = ____ 8 + ____ = ____ ____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____ b. 18 + 2 = ____ 18 + 4 = ____ 18 + 6 = ____ 18 + ____ = ____ ____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____ ____ + ____ = ____ c. 1 2 of 0 is ____. 1 2 of 2 is ____. 1 2 of 4 is ____. 1 2 of ____ is ____. 1 2 of ____ is ____. 1 2 of ____ is ____. 1 2 of ____ is ____.
Adding with 7
We have already studied these addition facts with 7:
These are the new facts with 7:
7 + 8 = ____ 7 + 9 = ____ 7 + 10 = ____ 8 + 7 = ____ 9 + 7 = ____ 10 + 7 = ____ 7 + 4 = ____ 7 + 5 = ____ 7 + 6 = ____ 7 + 7 = ____
1. First circle ten balls. Then add.
Use the list on the right to practice. Don't write the answers there. Just point to different problems and say the answer aloud.
2. Let's practice doubles - and doubles plus one more.
a. 7 + 7 10 + ___ = ____ b. 7 + 5 10 + ___ = ____ c. 7 + 6 10 + ___ = ____ a. 6 + 6 = ____ 6 + 7 = ____ b. 7 + 7 = ____ 7 + 8 = ____ c. 8 + 8 = ____ 8 + 9 = ____ d. 9 + 9 = ____ 9 + 10 = ____ d. 5 + 5 = ____ 6 + 5 = ____ d. 4 + 4 = ____ 4 + 5 = ____ 7 + 1 = 7 + 2 = 7 + 3 = 7 + 4 = 7 + 5 = 7 + 6 = 7 + 7 = 7 + 8 = 7 + 9 =
Here are some addition facts where we add to seven. Do not write the answers down but just go over them until you remember them easily.
3. Fill in the missing numbers.
7 + 0 = 7 + 3 = 7 + 10 = 7 + 5 = 7 + 9 = 7 + 8 = 7 + 6 = 7 + 7 = 7 + 1 = 7 + 9 = 7 + 4 = 7 + 2 = a. 7 + 4 = ____ 6 + 7 = ____ 7 + 5 = ____ b. 8 + 7 = ____ 7 + 10 = ____ 3 + 7 = ____ c. 7 + ____ = 14 7 + ____ = 13 7 + ____ = 15 d. 7 + ____ = 12 7 + ____ = 16 7 + ____ = 11 e. 7 + 7 = ____ 9 + 7 = ____ 7 + 8 = ____ f. 4 + 7 = ____ 7 + 9 = ____ 3 + 7 = ____ g. 8 + ____ = 13 8 + ____ = 16 8 + ____ = 17 h. ____ + 7 = 17 ____ + 7 = 10 ____ + 7 = 12
4. Try these boxes! Add 7 each time. Add 8 each time. Add 9 each time.
+ 7 4 7 8 10 5 3 9 11 ____ ____ ____ ____ ____ ____ + 8 3 6 5 7 9 2 4 11 ____ ____ ____ ____ ____ ____ + 9 2 4 7 8 3 6 5 ____ ____ ____ ____ ____ ____ ____
Adding with 6
Here are addition facts where we add to six. Do not write the answers down. Just go over the problems until you remember them easily.
1. Fill in the missing numbers.
2. Do not forget adding many numbers, either.
+ = 6 + 5 = ____ + = 6 + 6 = ____ 6 + 0 = 6 + 3 = 6 + 10 = 6 + 5 = 6 + 7 = 6 + 1 = 6 + 9 = 6 + 4 = 6 + 2 = 6 + 6 = 6 + 8 = a. 6 + 4 = _____ 6 + 6 = _____ 6 + 5 = _____ b. 6 + 8 = _____ 6 + 9 = _____ 6 + 7 = _____ c. 6 + ____ = 14 6 + ____ = 16 6 + ____ = 12 d. 6 + ____ = 13 6 + ____ = 15 6 + ____ = 11 e. 5 + 6 = _____ 6 + 7 = _____ 4 + 6 = _____ f. 9 + 6 = _____ 8 + 6 = _____ 6 + 6 = _____ g. 7 + ____ = 14 8 + ____ = 14 9 + ____ = 14 h. ___ + 6 = 13 ___ + 6 = 14 ___ + 6 = 15 a. 6 + 6 + 2 = _____ 10 + 4 + 5 = _____ b. 8 + 6 + 3 = _____ 20 + 2 + 5 = _____ c. 6 + 9 + 3 = _____ 50 + 6 + 4 = _____
Review - Facts with 6, 7, and 8
1. Here are the 20 addition facts with single-digit numbers where the sum is between 10 and 20. Connect the problems to the right answer.
2. Figure out the pattern and continue it.
6 + 6 5 + 8 9 + 5 5 + 6 3 + 9 7 + 7 8 + 3 11 12 13 14 8 + 6 5 + 7 9 + 2 4 + 7 9 + 4 6 + 7 4 + 8 15 16 17 18 9 + 9 7 + 9 8 + 7 9 + 8 8 + 8 6 + 9 a.
9 + ____ = 19
8 + ____ = 18
7 + ____ = 17
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
b.____ + 16 = 17
____ + 14 = 17
____ + 12 = 17
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
c.6 + ____ = 6
6 + ____ = 8
6 + ____ = 10
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
____ + ____ = ____
3. Fill in the addition table.
4. Try your skills!
5. Add in the easiest order. First find numbers that make 10!
+ 6 2 8 4 5 1 7 3 9 3 5 7 9 a. 6 + 9 = _____ 9 + 8 = _____ 4 + 9 = _____ 6 + 5 = _____ b. 8 + 9 = _____ 9 + 2 = _____ 7 + 6 = _____ 7 + 5 = _____ c. 5 + 9 = _____ 9 + 3 = _____ 4 + 8 = _____ 9 + 7 = _____ d. 6 + 6 = _____ 9 + 4 = _____ 3 + 9 = _____ 8 + 7 = _____
When you add lots of numbers, first add the numbers that form a ten. It makes adding easier!
8 + 6 + 4 = 8 + 10 = 18 5 + 6 + 2 + 5 = 10 + 8 = 18 a. 1 + 6 + 9 = _____ 5 + 4 + 7 = _____ 8 + 6 + 4 = _____ 5 + 6 + 5 = _____ b. 3 + 6 + 6 = _____ 3 + 5 + 7 = _____ 7 + 8 + 2 = _____ 3 + 6 + 4 = _____ c. 4 + 7 + 3 + 5 = _____ 6 + 5 + 1 + 4 = _____ 8 + 3 + 6 + 2 = _____ 9 + 6 + 1 + 4 = _____
Subtract to Ten
1. Subtract the "ones" that are not in the whole ten-groups. You should only have tens left!
2. First subtract so many that you have only 10 left. Then subtract the rest.
3. First subtract to 10. Then subtract some more.
a. 13 − 3 = 10 b. 15 − ____ = 10 c. 26 − ____ = ____ d. 38 − ____ = ____ e. 17 − ____ = 10 f. 21 − ____ = 20 g. 19 − ____ = 10 h. 64 − ____ = 60 Subtracting in parts
Let's subtract 13 − 5. First we subtract so many balls that we have only 10 left. So, we take away 3 balls. 13 − 3 = 10. Then, we subtract the rest, which means we subtract 2 more. 10 − 2 = 8.
13 − 5 / \ 13 − 3 − 2 10 − 2 = 8 a. 15 − 7 / \ 15 − 5 − 2 10 − 3 = ____ b. 13 − 8 / \ 13 − ___ − ____ 10 − ____ = ____ c. 13 − 4 / \ 13 − ___ − ____ 10 − ____ = ____ d. 14 − 9 / \ 14 − ___ − ____ 10 − ___ = ____ e. 12 − 5 / \ 12 − ___ − ____ 10 − ___ = ____ f. 16 − 8 / \ 16 − ___ − ____ 10 − ___ = ____ a. 13 − 6 / \ 13 − 3 − 3 = ____ b. 14 − 9 / \ 14 − ____ − ____ = ____ c. 15 − 8 / \ 15 − ____ − ____ = ____
4. First subtract to 10. Then subtract some more.
5. First subtract those that are not in the ten-group. Compare the top and bottom problems.
6. Subtract.
7. Subtract a number so that the answer is 10 or 9. Do you notice a shortcut?
8. Subtract in two steps. First subtract to the previous whole ten. Then, subtract some more. How much did you subtract (take away) all totaled?
a. 16 − 7 / \ 16 − ____ − ____ = ____ b. 12 − 4 / \ 12 −____ − ____ = ____ d. 13 − 6 / \ 13 − ____ − ____ = ____ d. 11 − 3 / \ 11 − ____ − ____ = ____ e. 12 − 7 / \ 12 − ____ − ____ = ____ f. 15 − 8 / \ 15 − ____ − ____ = ____ a. 15 − 7 = ____ b. 13 − 6 = ____ c. 16 − 9 = ____ d. 25 − 7 = ____ e. 23 − 6 = ____ f. 26 − 9 = ____ a. 12 − 4 = 12 − 5 = 12 − 3 = 12 − 6 = b. 15 − 6 = 15 − 9 = 15 − 7 = 15 − 8 = c. 14 − 5 = 14 − 8 = 14 − 7 = 14 − 6 = a. 13 − ____ = 10 13 − ____ = 9 b. 11 − ____ = 10 11 − ____ = 9 c. 15 − ____ = 10 15 − ____ = 9 d. 12 − ____ = 10 12 − ____ = 9 a. 29 − ____ = 20 20 − 5 = ____ I subtracted a total of ____. b. 34 − ____ = 30 30 − 3 = ____ I subtracted a total of ____. c. 72 − ____ = 70 70 − 6 = ____ I subtracted a total of ____.
