Переводим все дроби в неправильные и приводим к общему знаменателю 60.
5 7/15 = (5*15+7)/15 = 82/15 = 82*4/60 = 328/60
7 1/12 = (7*12+1)/12 = 85/12 = 85*5/60 = 425/60
4 29/60 = (4*60+29)/60 = 269/60
2 1/5 = (2*5+1)/5 = 11/5 = 11*12/60 = 132/60
1 5/6 = (6+5)/6 = 11/6 = 110/60
Теперь считаем
328/60 - (425/60 - (269/60 - (132/60 - 110/60))) = 328/60 - (425/60 - (269/60 - 22/60)) =
= 328/60 - (425/60 - 247/60) = 328/60 - 178/60 = 150/60 = 15/6