Question

for numbers 6a-6d, tell which expressions require you to rename mixed numbers before you can subtract.Find each difference. Write each expression and the difference in the correct box.

Answer 1

- A) 5 2/5-2 1/4 common denominator 20/

8//20-5/20=3 3/20 no renaming needed

B) 5-2 7/8 renaming needed

4 8/8- 2 7/8= 40/8-7/8

2 1/8

C) 7 2/3-6 1/8= common denominator 24

16/24-3/24=1 13/24 no renaming needed

D) 9 1/6-5 2/3= renaming needed

8 7/6-5 2/3 common denominator of 6

7/6--4/6=3 1/2

Answer 2

Requires renaming

5 - 2 7/8 = 2 1/8

7 2/3 - 6 1/8 = 5 5/8

9 1/6 - 5 2/3 = 3 1/2

Does not require renaming

5 2/5 - 2 1/4 = 3 3/20

Explanation:

6a) Given the expression

5 2/5 - 2 1/4

We do not need to rename both mixed fraction before subtracting.

The expression can be rewritten as:

(5-2)+(2/5-1/4)

3 + (2/5-1/4)

Solving 2/5-1/4 = 8-5/20

= 3/20

5 2/5 - 2 1/4 = 3 + 3/20

5 2/5 - 2 1/4 = 3 3/20

b) 5 - 2 7/8

We need to rename the mixed fraction 2 7/8 before subtracting

5 - 23/8

Taking their LCM

= 40-23/8

= 17/8

= 2 1/8

c) 7 2/3 - 6 1/8

We need to rename both mixed fraction before subtracting.

The expression can be rewritten as:

23/3 - 49/8

= 184-49/24

= 135/24

= 45/8

= 5 5/8

d) 9 1/6 - 5 2/3

We need to rename both mixed fraction before subtracting. The expression can be rewritten as:

55/6 - 17/3

= 55-34/6

= 21/6

= 7/2

= 3 1/2