1)6 1/4 × 8 = 25/4 × 8 = 50
2)3 2/3 × 5 1/2 = 11/3 × 11/2 = 121/6 = 20 1/6
3)2 2/5 × 4 7/12 = 12/5 × 55/12 = 11
4)50 - 20 1/6 = 50/1 - 121/6 =(50 × 6 - 121 × 1)/6 = 300/6 - 121/6 = 179/6 = 29 5/6
5)29 5/6 + 11 = 179/6 + 11 =(179 × 1 + 11 × 6)/6 = 179/6 + 66/6 = 245/6 = 40 5/6
Ответ : 40 5/6