1 2/3 : 2 1/2 - 3/5 x x 1 2/7

1 2/3 = 5/3
2 1/2 = 5/2
1 2/7 = 9/7

(5/3 : 5/2) - (3/5 × 9/7)
5/3 : 5/2 = 3/2

3/5 × 9/7 = 27/35

*dikurang*

3/2 - 27/35 = ...

*disamakan penyebutnya*

105/70 - 54/70 = 51/70

*jadi*

1 2/3 : 2 1/2 - 3/5 × 1 2/7 = 51/70