Mathematics 2
Having Fun Adding and Subtracting
Day 8: Relating Addition and Subtraction
©PhotoDisc, Inc.
Today you will mix up addition and subtraction. It means you have to watch the signs.
Along with Elena and Jasper, you will be amazed to see how the same three numbers can be used to write
four number sentences.
You will use domino cards for some of the activities today.
Are you ready to begin? Let's mix it up!
Lesson 1
1. How many can you do in two minutes? Watch the signs!
| a. 9 - 6 = ________ |
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f. 8 - 4 = ________ |
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k. 6 + 1 = ________ |
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p. 5 - 5 = ________ |
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| b. 10 - 2 = ________ |
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g. 6 + 4 = ________ |
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l. 8 - 6 = ________ |
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q. 9 - 2 = ________ |
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| c. 4 + 3 = ________ |
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h. 9 - 3 = ________ |
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m. 7 - 5 = ________ |
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r. 3 + 1 = ________ |
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| d. 10 - 7 = ________ |
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i. 8 - 7 = ________ |
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n. 5 + 4 = ________ |
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s. 6 + 2 = ________ |
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| e. 9 - 4 = ________ |
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j. 5 + 1 = ________ |
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o. 5 + 2 = ________ |
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t. 7 - 6 = ________ |
How many did you do?
2. Solve these problems. For each problem, write the number sentence. Then answer the problem in a
complete sentence.
a. Jasper read four books the first week he joined the reading club. He then read three books
the second week. How many more books did he read the first week?
_____ - _____ = _____
b. Elena did a magic trick. She put seven candies in a cloth and wrapped them up. When she
opened the cloth, there were only four candies. How many candies disappeared?
_____ - _____ = _____
c. Jasper counted nine chocolate chips in his cookie. Elena counted three fewer than that in her
cookie. How many chocolate chips did Elena have in her cookie?
_____ - _____ = _____
Lesson 2
Elena and Jasper were amazed one day when they discovered that they could write four number sentences
from the same numbers! This is what they saw.
Jasper wrote the addition sentences.
4 + 5 = 9
5 + 4 = 9
Elena wrote the subtraction sentences.
9 - 5 = 4
9 - 4 = 5
She first took the total number of dots, then subtracted one half, then the other half.
Jasper and Elena saw that this is what it means when numbers are related.
Choose a manipulative from your Math Box.
Use your manipulative to make the number sentences Jasper and Elena made. Do you see how the three
numbers are related?
See for yourself how this works.
Take out a blank Domino Card from your Student Folder.
Select ten manipulatives from your Math Box.
Your home instructor will show you what to do. After you place your manipulatives on your card, write the
number sentences.
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Have the student place some manipulatives on each side of a blank Domino Card and then write
addition and subtraction number sentences to show the number of objects on the card.
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Lesson 3
You will need the picture Domino Cards from your Student Folder.
You will be using the Domino Cards for this activity. Your home instructor will show you what to do.
Write the number sentences.
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Provide the student with four picture Domino Cards. Have the student write the addition and
subtraction number sentences to show the total number of dots on the card.
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1. Show two different addition sentences for each. Look at the following example.
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4 |
+ |
3 |
= |
7 |
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3 |
+ |
4 |
= |
7 |
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| a. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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b. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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| c. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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d. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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| e. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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f. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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| g. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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2. Show two different subtraction sentences for each. Look at the following example.
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7 |
- |
5 |
= |
2 |
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7 |
- |
2 |
= |
5 |
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| a. |
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 |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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b. |
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 |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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| c. |
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 |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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d. |
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 |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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| e. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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f. |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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| g. |
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 |
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| _____ |
+ |
_____ |
= |
_____ |
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| _____ |
+ |
_____ |
= |
_____ |
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3. Make four number sentences (two addition and two subtraction) for each group of numbers. An
example has been done for you.
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|
| 5 + 4 = 9 |
| 4 + 5 = 9 |
| 9 - 5 = 4 |
| 9 - 4 = 5 |
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