Reteaching
Name
10-2
Modeling Addition and
Subtraction of Mixed Numbers
3
7 ​+ 2​ __
Example 1: Draw a model to add 1​ __
 ​.
8
8
Step 1 Model each mixed number using
fraction strips.
1
1
1
1
8
1
8
1
8
1
8
1
8
1
8
1
8
1
8
1
8
1
8
Step 2 Add the fractions. Regroup if you can.
7 ​
​ __
8
__
+ ​ 3 ​
8
10
2 ​
___
​    ​ =1​ __
8
8
1
8
1
8
1
8
1
8
1
8
1
8
1
8
Step 3 Add the whole
numbers to the regrouped
fractions. Write the sum.
Simplify, if possible.
7
8
So, 1__
​   ​ +
1
8
1
8
1
8
8
8
1
2
8
left
1
1
8
1
8
1
1
1
1
8
1
1
8
3
1
2__
​   ​  = 4__
​   ​. 
8
4
1 ​– 1​ __
2 ​.
Example 2: Draw a model to subtract 2​ __
5
5
6
1 ​as 1​ __
Step 2 Rename 2​ __
 ​. Cross out one
5
5
Step 1 Model the number you are
2 ​.
whole and __
​ 25 ​to show subtracting 1​ __
5
1 ​.
subtracting from, 2​ __
5
1
1
1
5
1
1
5
1
5
1
5
1
5
1
5
4
5
1
5
Express the part of the model that is not crossed out as a fraction
1 ​–1​ __
2 ​= __
​ 45 ​.
or mixed number. So, 2​ __
5
5
Use fraction strips to find each sum or difference. Simplify, if possible.
1 ​+ 1​ __
1 ​
1. 3​ __
5
3
2. 2​ __
 ​+ 4​ __ ​
5
2 ​+ 3​ __
3. 5​ __
 ​
3
2 ​+ 6​ __
4. 2​ __
 ​
5
1 ​– 3​ __
 ​
5. 6​ __
3
5
6. 8​ ___
  ​ – 2​ ___  ​  1 ​– 5​ __
2 ​
7. 12​ __
9
7   ​– 6​ ___
8. 9​ ___
  ​ 
2
8
2
8
8
12
8
12
6
6
3
R 10•2
3
4
10
4
10
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Practice
Name
10-2
Modeling Addition and
Subtraction of Mixed Numbers
For 1 and 2, use each model to find each sum or difference.
3
7 ​
 ​+ 1​ __
1. 1​ __
8
1 ​– 1​ __
4 ​
2. 3​ __
5
5
8
1
1
1
8
1
8
1
8
1
1
5
1
1
8
1
8
1
8
1
8
1
8
1
8
1
8
1
5
1
5
1
5
1
5
1
5
Use fraction strips to find each sum or difference.
Simplify, if possible.
1 ​+ 1​ __
2 ​
3. 2​ __
3
3
5
3
4. 3​ __
 ​+ 4​ __ ​
1 ​– 1​ __
2 ​
5. 5​ __
3
5
6. 12​ __
 ​– 2​ __ ​
5
1 ​– 3​ __
7. 8​ __
 ​
6
7  ​ 
8. 4​ ___
   ​+ 5​ ___
1 ​– 4​ __
2 ​
9. 7​ __
2 ​+ 3​ __
4 ​
10. 6​ __
5
5
6
6
5
1 ​+ 3​ __
11. 1​ __
 ​
6
6
6
10
6
10
4 ​+ 6​ __
7 ​
12. 2​ __
9
9
4
4
9
8
9
3
3
13. 6​ __
 ​– 4​ __ ​
5
5
8
1 ​– 4​ __
2 ​
14. 5​ __
3
3
9
   ​centimeters (cm) at the end of last month.
15. Jerome’s rain gauge showed 13​ __
10
3
  ​ centimeters. How many
At the end of this month, the rain gauge showed 15​ __
10
more centimeters of rain fell this month?
2  ​ cm
A 29​ ___
10
3
B 15​ ___
  ​ cm
10
4   ​cm
C 2​ ___
10
4   ​cm
D 1​ ___
10
16. You are adding 3​ _23 ​ + 2​ _23 ​ using fraction strips. Explain how you rename the
fraction part of the problem.
P 10•2
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