1) 53/60 - 37/84 = 371/420 - 185/420 = 31/70
2) 3/14 + 12/35 = 15/70 + 24/70 = 39/70
3) 340/567 + 29/42 = 680/1134 + 783/1134 = 209/162 = 1 47/162
4) 209/162 + 43/54 = 209/162 + 129/162 = 169/81 = 2 7/81
5) 169/81 + 74/81 = 3
6) 3 - 31/70 = 179/70 = 2 39/70
7) 2 39/70 - 39/70 = 2
Ответ: 2