Вычислите 2цел2/5-(1/4+7/10); 3цел-(1/6+2/3); 7-(2цел3/4+7/12).

2 2/5 - (1/4 + 7/10) = 2 2/5 - (10+28)/40 = 12/5 - 38/40 = (96-38)/40 = 58/40 = 1 18/40 = 1 9/20

3 - (1/6 + 2/3) = 3 - (1+6)/6 = 3/1 - 7/6 = (18-7)/6 = 11/6 = 1 5/6

7 - (2 3/4 + 7/12) = 7 - (15/4 + 7/12) = 7 - (45+7)/12 = 7/1 - 52/12 = (84-52)/12 = 32/12 = 2 8/12 = 2 2/3