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common denominator
equivalent fractions
what's the sum?
What's the difference?
100

1/10 + 3/10

10

100

1/2 = 2/?

4

100

2/5 + 3/10 =

7/10

100

7/8 - 4/8=

3/8

200

5/6 + 2/6

10

200

6/8 = 12/?

16

200

1/2 + 3/4 =

5/4 or 1 1/4

200

8/9 - 4/9 =

4/9

300

1/4 + 2/12

12

300

4/10 = ?/5

2

300

3/8 + 1/4 = 

5/8

300

5/7 - 2/14=

8/14

400

5/10 + 4/100

100

400

10/20 = ?/2

1

400

5/6 + 1/2=

8/6 or 1 2/6 or 1 1/3

400

7/10 - 2/5 =

3/5

500

3/8 + 2/3

24

500

20/40 = 40/?

80

500

4/3 + 5/12 =

21/12 or 1 9/12 or 1 3/4

500

21/25 - 2/5 =

11/25