1) 3/4 + 5/7 = 21/28 + 20/28 = 41/28

2) 9/14 - 3/4 = 9/14 - 21/28 = 18/28 - 21/28 = -3/28

3) 11/12 - 2/3 = 11/12 - 8/12 = 3/12 = 1/4

4) 7/25 + 4/10 = 28/100 + 40/100 = 68/100 = 17/25

5) 11/18 - 5/12 = 22/36 - 15/36 = 7/36

6) 13/18 + 7/15 = 65/90 + 42/90 = 107/90

7) 19/24 - 25/36 = 63/72 - 50/72 = 13/72

8) 5/6 - 3/4 + 5/24 = 20/24 - 18/24 + 5/24 = 7/24

9) 5/8 + 11/28 - 9/14 = 35/56 + 22/56 - 36/56 = 21/56