Решить (7/8-3/5)÷(2/3+1/2)×(60целых ÷ 4целых5/7) заранее

(7/8 - 3/5) : (2/3 + 1/2) * (60 : 4 5/7) = 3

1) 7/8 - 3/5 = 35/40 - 24/40 = 11/40
2) 2/3 + 1/2 = 4/6 + 3/6 = 7/6
3) 60 : 4 5/7 = 60 : 33/7 = 60 * 7/33 = (20*7)/11 = 140/11
4) 11/40 : 7/6 = 11/40 * 6/7 = (11*3)/(20*7) = 33/140
5) 33/140 * 140/11 = 33/11 = 3