Дарю 35 (7целых3/5 * (-2,5) - 4целых3/20 * (-10) * (2 - 3целых4/25).

3 4/7 - 2 3/5 = 3 20/35 - 2 21/35 = 2 55/35 - 2 21/35 = 34/35
6 6/5 + 2 3/8 = 7 1/5 + 2 3/8 = 7 8/40 + 2 15/40 = 9 23/40  
(6/5 - неправильная дробь)
6 5/6 + 2 3/8 = 6 20/24 + 2 9/24 = 8 29/24 = 9 5/24

4 5/14 + (5 1/12 - 3 4/21) = 6 1/4
1) 5 1/12 - 3 4/21 = 5 7/84 - 3 16/84 = 4 91/84 - 3 16/84 = 1 75/84 = 1 25/28
2) 4 5/14 + 1 25/28 = 4 10/28 + 1 25/28 = 5 35/28 = 6 7/28 = 6 1/4