Выполните действия 3 2/7-6/7;1 1/3x4;3 1/4x2/5;2 1/4:3;20:2 1/2

Вычислим значения выражений:

1) 3 2/7 - 6/7 = 3  + 2/7 - 6/7 = 3 + (2 - 6)/7 = 3 - 4/7 = 2 + 1 - 4/7 = 2 + 7/7 - 4/7 = 2 + (7 - 4)/7 = 2 + 3/7 = 2 3/7;

2) 1 1/3 x 4 = (1 * 3 + 1)/3 * 4 = 4/3 * 4 = 16/3 = 15/3 + 1/3 = 3 + 1/3 = 3 1/3;

3) 3 1/4 x 2/5 = (3 * 4 + 1)/4 * 2/5 = 13/4 * 2/5 = 13/5 * 2/4 = 13/5 * 1/2 = 13/10 = 10/10 + 3/10 = 1 + 3/10 = 1 3/10;

4) 2 1/4 : 3 = (2 * 4 + 1)/4 : 3 = (8 + 1)/4 : 3 = 9/4 : 3 = 9/4 * 1/3 = 9/12 = 3/4;

5) 20 : 2 1/2 = 20 : (2 * 2 + 1)/2 = 20 : 5/2 = 20 * 2/5 = 20/5 * 2 = 4 * 2 = 8.