13 11/12-10

4 4/15-2 1/30

12 1/5+2 5/10

15 1/7-5

16 2/9+2 1/18

13 11/12-10=3 11/12

4 4/15-2 1/30= 4 8/30- 2 1/30=2 7/30

12 1/5+2 5/10= 12 2/10 - 2 5/10 =9 7/10

15 1/7-5 = 10 1/7

16 2/9+2 1/18= 16 4/18 + 2 1/18= 18 5/18