Reteaching
Name
10-3
Modeling Addition and
Subtraction of Mixed Numbers
5
1 ​.
Example 1: Draw a model to add 2​ __
 ​+ 2​ __
8
2
Step 1 Rename the fractions as equivalent
1 ​= 1​ __
4 ​
fractions with like denominators. 1​ __
2
8
Model each mixed number using fraction strips.
1
1
1
8
1
8
1
8
1
8
1
1
1
8
1
8
1
8
1
8
1
8
Step 2 Add the fractions. Regroup if you can.
5
​ __
 ​
8
__
+ ​ 4 ​
8
9
1 ​
__
​   ​ =1​ __
8
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.
5
8
So, 2__
​   ​  +
1
8
1
8
1
8
1
8
8
8
1
2
8
left
1
1
8
1
1
1
4
1
2__
​   ​  = 5__
​    ​.
8
8
1
1
8
1
1 ​– 1​ __
2 ​.
Example 2: Draw a model to subtract 2​ __
5
5
Step 1 Rename the fractions as equivalent fractions with
6
3
like denominators. 1​ ___
  ​ = 1​ __ ​Model the number you are
5
10
1 ​.
subtracting from, 2​ __
5
6
1 ​as 1​ __
Step 2 Rename 2​ __
 ​. Cross out one
5
5
whole and __
​ 35 ​to show subtracting __
​ 35 ​.
1
1
1
5
1
1
5
1
5
1
5
1
5
3
5
1
5
1
5
Express the part of the model that is not crossed out as a fraction
6
1 ​– 1​ ___
  ​ = __
​ 35 ​.
or mixed number. So, 2​ __
5
10
Use fraction strips to find each sum or difference. Simplify, if possible.
3
1 ​+ 1​ __
1. 3​ __
 ​
1 ​+ 4​ __
7 ​
2. 5​ __
8
1 ​+ 1​ __
2 ​
3. 6​ __
3
5
4. 8​ __
 ​+ 1​ __ ​
1 ​– 4​ __
7 ​
5. 5​ __
2 ​ 6. 6 – 2​ __
5
11  ​
7. 4​ __
 ​– 2​ ___
3
1 ​
8. 8​ __
 ​– 2​ __
2
3
4
8
3
3
4
6
R 10•3
3
12
4
4
6
6
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