выполните вычитание :1-2/5; 6-3/7; 5 2/3-4; 6-1 1/2; 7 5/8-1/8.

1) 1 - 2/5 = 5/5 - 2/5 = (5 - 2)/5 = 3/5;

2) 6 - 3/7 = 6 * 7/7 - 3/7 = 42/7 - 3/7 = (42 - 3)/7 = 39/7;

3) 5 2/3 - 4 = (5 * 3 + 2)/3 - 4 = (15 + 2)/3 - 4 = 17/3 - 4 * 3/3 = 17/3 - 12/3 = (17 - 12)/3 = 5/3;

4) 6 - 1 1/2 = 6 - (1 * 2 + 1)/2 = 6 - 3/2 = 12/2 - 3/2 = (12 - 3)/2 = 9/2;

5) 7 5/8 - 1/8 = (7 * 8 + 5)/8 - 1/8 = (56 + 5)/8 - 1/8 = 61/8 - 1/8 = (61 - 1)/8 = 60/8 = 15/2.