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10Multiply Mixed Numbers Unit
2 . Multiply. Students are now familiar with both methods
of multiplying mixed numbers and whole
a. 2 1 4 = 9 1 b. 3 4 2 = 7 3 numbers. Ask them a few questions to
3 3 5 5 review.
What’s the final step in the first method?
c. 4 3 5 = 23 3 d. 2 3 7 = 16 5 Adding the products together.
4 4 8 8 What’s the final step in the second
method? Dividing the improper fraction
ng 3 . Solve the word problems. created by multiplying.
Which method involves fewer steps?
nd a. 2 3 hours on Saturday. Jessica studied 3 times more Both methods have the same number of
5 steps.
Thomas studied Which method do you prefer?
hours than Thomas did. How many hours did Jessica study?
3 2 3 = 7 4 2. Have students solve the problems using
5 5 the method of their choice.
7 4 hours 3. Have students solve the word problems.
5
b. Ryan used 1 2 cans of paint to paint his mother’s room. If each can has
3
5 gallons of paint, how many gallons of paint did he use?
5 1 2 = 8 1
3 3
8 1 gallons
3
10. Multiply Mixed Numbers 91
When using the improper fraction method, students may make the error of failing to properly multiply the
fraction by the whole number.
Example: 22 5
4
Students may incorrectly multiply both the numerator and the denominator by 5, resulting in an incorrect
answer.
22 5 110 Incorrect
4 5 20
Remind students that the correct method involves placing a 1 as the denominator of the whole number.
5A Unit 10 147
2 . Multiply. Students are now familiar with both methods
of multiplying mixed numbers and whole
a. 2 1 4 = 9 1 b. 3 4 2 = 7 3 numbers. Ask them a few questions to
3 3 5 5 review.
What’s the final step in the first method?
c. 4 3 5 = 23 3 d. 2 3 7 = 16 5 Adding the products together.
4 4 8 8 What’s the final step in the second
method? Dividing the improper fraction
ng 3 . Solve the word problems. created by multiplying.
Which method involves fewer steps?
nd a. 2 3 hours on Saturday. Jessica studied 3 times more Both methods have the same number of
5 steps.
Thomas studied Which method do you prefer?
hours than Thomas did. How many hours did Jessica study?
3 2 3 = 7 4 2. Have students solve the problems using
5 5 the method of their choice.
7 4 hours 3. Have students solve the word problems.
5
b. Ryan used 1 2 cans of paint to paint his mother’s room. If each can has
3
5 gallons of paint, how many gallons of paint did he use?
5 1 2 = 8 1
3 3
8 1 gallons
3
10. Multiply Mixed Numbers 91
When using the improper fraction method, students may make the error of failing to properly multiply the
fraction by the whole number.
Example: 22 5
4
Students may incorrectly multiply both the numerator and the denominator by 5, resulting in an incorrect
answer.
22 5 110 Incorrect
4 5 20
Remind students that the correct method involves placing a 1 as the denominator of the whole number.
5A Unit 10 147
