Page 211 - NUMINO TG_5A

070_G5U13_G6U15_TG 2014.4.18 3:34 PM ˘ ` 194

Activity 3 Dividing Fractions

jOb ective Divide fractions with different denominators.

1. Textbook Instructions Activity 3 Dividing Fractions

Learn how to divide fractions.

Solve the example for students.

Example: 3 9 Divide. 3 9
4 10 4 10

Find the reciprocal of the divisor, just as you Find the reciprocal of 3 9 3 10 15
the divisor to write 4 10 4 9
a multiplication sentence. 3 9 3 10
30
would dividing a whole number by a fraction. 36 4 10 4 9

5 2 3
6
5

Create a multiplicati on sentence with the 6

reciprocal. 10 Write the fraction in
9 simplest form.
393
4 10 4

Multiply. Now students will learn to divide fractions with different denominators. Again, they will use a
reciprocal to write a multiplication sentence.
3 10 30
4 9 36 1 . Solve the division problems.

Simplify the fraction. a. 2 32 5 b. 7 77 9
3 53 8 98
30 5 3 7
36 6
10 9

98

1. Have students use reciprocals to divide 1 1
fractions.
1 1
9 8

c. 5 25 7 d. 3 53 8
6 76 2 4 84 5

35 6

12 5

11 1
2
1
12 5

120

2. Build Understanding

Every fraction must be simplified in order find quotient. Rather than simplifying the fraction after finding its

quotient, students can simplify the numerators and denominators of the fractions and then solve to get the

same answer.

Example: 3 9 3 10
4 10 4 9
13 10 1 10
Step 1: Cross reduce 3 and 9. 4 593 4 3
10
Step 2: Cross reduce 4 and 10. 1 3 1 5
42 2 3

Step 3: Multiply. 1 5 5
2 3 6

194 NUMINO Teacher s Guide