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070_G5U13_G6U15_TG 2014.4.18 3:34 PM ˘ ` 191
13Flip It Over Unit
Method 2 Use a reciprocal. Method 2: Use reciprocals
Divide. 2 1 Example: 2 1
4 4
Find the reciprocal of the divisor. Rather than strictly divide, use a reciprocal.
1 4 1 When the product Find the reciprocal by flipping the fraction.
4 1
of two numbers is 1 4
reciprocals 1, the numbers are 4 1 1
reciprocals.
Use the reciprocal to write a multiplication sentence. 4
1
2 1 2 4 8 is the reciprocal.
4 1
Multiply the whole number by the
2 . Divide a whole number by a fraction using a reciprocal. reciprocal.
a. 2 1 5 b. 2 1 2 2 4 = 8 8
5 1 2 1 1 1
2\ 10 2\ 4
c. 3 1 3\ 5 15 d. 4 1 4\ 6 24 2. Have students divide fractions using
5 1 6 1 reciprocals.
3. Have students solve the word problems.
3 . Solve the word problems.
3. Check Point
a. There is a ribbon that is 3 m long. 1 m of ribbon is needed to tie 1 box.
4
How many boxes can be tied with the ribbon? 4
1 1
3ı 4 3\ 12 The Parts of a Division Equation
12 boxes
b. There is 7 L of water in a bucket. How many 1 L bottles are needed to Vertical Division Division Equation
6
1 2 quotient division equal to
6 dividend sign sign
pour all of the water into the L bottles? 1 6 8 21 2 1 2
7ı 6 7\ 1 42 divisor -16 remainder 3 4 2 3
42 bottles 5 dividend divisor quotient
13. Flip It Over 117
When dealing with reciprocals, students can make the error of failing to properly multiply by the correct number.
Rather than multiplying the whole number by the reciprocal’s numerator and then simplifying the product,
students may multiply the whole number by both sides of the reciprocal, resulting in an incorrect simplification.
Example: 2 4 8 4
1 2
This is incorrect. Remind students of the correct reciprocal method.
5A Unit 13 191
13Flip It Over Unit
Method 2 Use a reciprocal. Method 2: Use reciprocals
Divide. 2 1 Example: 2 1
4 4
Find the reciprocal of the divisor. Rather than strictly divide, use a reciprocal.
1 4 1 When the product Find the reciprocal by flipping the fraction.
4 1
of two numbers is 1 4
reciprocals 1, the numbers are 4 1 1
reciprocals.
Use the reciprocal to write a multiplication sentence. 4
1
2 1 2 4 8 is the reciprocal.
4 1
Multiply the whole number by the
2 . Divide a whole number by a fraction using a reciprocal. reciprocal.
a. 2 1 5 b. 2 1 2 2 4 = 8 8
5 1 2 1 1 1
2\ 10 2\ 4
c. 3 1 3\ 5 15 d. 4 1 4\ 6 24 2. Have students divide fractions using
5 1 6 1 reciprocals.
3. Have students solve the word problems.
3 . Solve the word problems.
3. Check Point
a. There is a ribbon that is 3 m long. 1 m of ribbon is needed to tie 1 box.
4
How many boxes can be tied with the ribbon? 4
1 1
3ı 4 3\ 12 The Parts of a Division Equation
12 boxes
b. There is 7 L of water in a bucket. How many 1 L bottles are needed to Vertical Division Division Equation
6
1 2 quotient division equal to
6 dividend sign sign
pour all of the water into the L bottles? 1 6 8 21 2 1 2
7ı 6 7\ 1 42 divisor -16 remainder 3 4 2 3
42 bottles 5 dividend divisor quotient
13. Flip It Over 117
When dealing with reciprocals, students can make the error of failing to properly multiply by the correct number.
Rather than multiplying the whole number by the reciprocal’s numerator and then simplifying the product,
students may multiply the whole number by both sides of the reciprocal, resulting in an incorrect simplification.
Example: 2 4 8 4
1 2
This is incorrect. Remind students of the correct reciprocal method.
5A Unit 13 191
