(1 1/7-2/5): (3/5+7/20)*1 6/13-3/26*5 1/5: 3/5

(1 1/7 - 2/5) : (3/5 + 7/20) * 1 6/13 - 3/26 * 5 1/5 : 3/5 = 1/7

1) 1 1/7 - 2/5 = 1 5/35 - 14/35 = 40/35 - 14/35 = 26/35
2) 3/5 + 7/20 = 12/20 + 7/20 = 19/20
3) 26/35 : 19/20 = 26/35 * 20/19 = 104/133
4) 104/133 * 1 6/13 = 104/133 * 19/13 = 8/7 = 1 1/7
5) 3/26 * 5 1/5 = 3/26 * 26/5 = 3/5
6) 3/5 : 3/5 = 1
7) 1 1/7 - 1 = 1/7

1 1/7 -2/5=8/7-2/5=40/35-14/35=26/35

3/5+7/20=12/20+7/20=19/20

26/35÷19/20×1 6/13=
=26/35×20/19×19/13=8/7=1 1/7

3/26×5 1/5÷3/5=3/26×26/5×5/3=1

1 1/7-1=1/7