1. 117-1/20=116/20
2 14-2/9= 12/9
3. 61/3-7/12=61*4/12-7/12=
244-7/12=237/12
4. 37/10-1/2=37/10-5/10=37-5/10=32/10=16/5
5. 62/3-22/25=1550/75-
66/75=1484/75
6. 91-11/2=80/2=40
7. 31/3-5/6=31*2/6-5/6=62-5/6=57/6
8. 61/2-15/12=61*6/2*6-15/12=
366/12-15/12=366-15/12=351/12
=351:3/12:3=117/4
9. 39/10-21/5=39/10-21*2/10=39-21*2/10=39-42/10=-3/10
10. 21/3-11/18=21*6/3*6-11/18=22*6-11/18=132-11/18=121/18
11. 37/9-21/3=37/9-21*3/3*3=37-21*3/9=37-63/9=-26/9
12. 81/6-31/8=81*8-31*6 /6*8=
648-186/48=462/48=462:2/48:2=
231/24=231:3/24:3=77/8
13. 21/2-16/13= 21*13/13*2-16*2/13*2=273/26-32/26=273-32/26=241/26
14. 71/3-32/9=71*3/3*3-32/9=
213-32/9=181/9
15. 21/2-14/15=21*15/2*15-14*2/15*2=21*15-14*2/30=315-28/30=
287/30