Practice
Name
12-8
Adding Mixed Numbers
In 1 through 6, find each sum. Simplify, if possible. Estimate for reasonableness.
5
2 + 8__
1. 7__
6
6
9
2
3. 11___
+ 3___
10
10
8
5
5. 5___
+ 3___
12
12
16_16
1
15__
10
1
9__
12
7_14
_3
9
2
__
__
13
7 +5
8
8
8
_1
5 39
11
___
___
21 + 17
3
12
12
3
2
2. 4__
+ 2__
4
4
4.
6.
7. Number Sense Write two mixed numbers that have a sum of 3.
Sample answer: 1_14 + 1_34 = 3
8. What is the total
measure of an average
man’s brain and heart
in kilograms (kg)?
7
1__
kg
10
Vital Organ Measures
Average woman’s brain
3
1___
kg
8
2___
lb
Average man’s brain
4 kg
1___
3 lb
Average human heart
3
___
kg
10
7 lb
___
10
9. What is the total weight of an average
woman’s brain and heart in pounds (lb)?
10. What is the sum of the measures of an average
man’s brain and an average woman’s brain in
kilograms?
10
10
10
3_12 lb
7
2__
kg
10
11. Which is a good comparison of the estimated
9
11
+ 2__
?
sum and the actual sum of 7__
12
12
A Estimated < actual
C Actual > estimated
B Actual = estimated
D Estimated > actual
12. Can the sum of two mixed numbers be equal to 2? Explain why or why not.
No; Sample answer: It is impossible for
two mixed numbers to equal 2 because
every mixed number is greater than 1.
P 12•8
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