Transcript Dividing Fractions and Mixed Numbers (4

COURSE 2 LESSON 4-5
Dividing Fractions and Mixed Numbers
Find 4 2 ÷ 1 3 .
3
4 2 ÷ 1 3 = 14 ÷ 7
3
4
3
4
14 4
= 3 • 7
2
14 • 4
= 3•7
1
8
4
Write the mixed numbers as improper fractions.
Multiply by the reciprocal of 7 , which is 4 .
4
Divide 14 and 7 by their GCF, which is 7.
Multiply.
= 3
=22
3
Write as a mixed number.
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7
COURSE 2 LESSON 4-5
Dividing Fractions and Mixed Numbers
You have a piece of yarn that is 12 1 ft long. You need to cut it
2
into strips that are 1 1ft long. How many strips will you have?
4
To find how many 1 1 -ft long strips are in 12 1 ft, divide 12 1 by 1 1 .
4
Estimate 12 1 ÷ 1 1
2
4
12 1 ÷ 1 1 = 25 ÷ 5
2
4
2
=
4
25 4
•
2
5
5 2
= 25 • 4
2•5
1 1
2
2
4
12 ÷ 1, or 12
Write the mixed numbers as improper fractions.
Multiply the reciprocal of 5 , which is 4 .
4
Divide 25 and 5 by their GCF, 5.
Divide 4 and 2 by their GCF, 2.
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5
COURSE 2 LESSON 4-5
Dividing Fractions and Mixed Numbers
(continued)
= 10 = 10
Simplify.
1
There are ten 1
1
1
-ft strips of yarn in 12 ft.
4
2
Check for Reasonableness The answer, 10, is close to the estimate, 12.
The answer is reasonable.
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COURSE 2 LESSON 4-5
Dividing Fractions and Mixed Numbers
Find each quotient.
1. 1 ÷ 3
8
2. 2 ÷ 3
4
3
1
6
1
3. 1 5 ÷ 2 2
6
8
7
9
4. 3 2 ÷ 1
5
7
55
72
21
4-5
3
7
5