1) 12! 5/7-7! 1/6=5! (30/42-7/42)=5! 23/42
2) 7! 1/4-3! 7/15=7! 15/60-3!28/60 =6! 75/60-3!28/60=3! 47/60
3) 9!5/12-6! 2/7=9! 35/84-6! 24/84 =3!11/84
4) 4! 1/6-2! 4/21=4! 7/42-2!8/42= 3!49/42-2! 8/42=1! 41/42
5)5! 9/25- 3! 8/15=5!27/75-3! 40/75 =4! 102/75-3! 40/75=1!62/75
6)4! 3/35-2! 5/14=4! 6/70- 2! 25/70= 3! 76/70-2!25/70=1!51/70
7) 10! 3/8- 4! 2/3=10! 9/24-4! 16/24 =9! 33/24-4! 16/24=5! 17/24
8) 7! 1/16-3! 5/24=7! 3/48- 3! 10/48= =6! 51/48-3! 10/48=3! 41/48