Выполните действие 3 целых 1/3÷2/3×1/5; 2) 4/5 ×2 целых 1/2÷6; 3) 3 целых 1/5×5/8÷2/7.

Выполним действия:

1. 3 1/3 : 2/3 * 1/5 = 1;

1) 3 1/3 : 2/3 = (3 * 3 + 1)/3 : 2/3 = (9 + 1)/3 : 2/3 = 10/3 : 2/3 = 10/3 * 3/2 = (5 * 2 * 3)/(3 * 2) = 5;

2) 5 * 1/5 = 5/5 = 1.

2. 4/5 * 2 1/2 : 6 = 1/3;

1) 4/5 * 2 1/2 = 4/5 * (2 * 2 + 1)/2 = 4/5 * (4 + 1)/2 = 4/5 * 5/2 = (2 * 2 * 5)/(5 * 2) = 2;

2) 2 : 6 = 2 * 1/6 = 2/6 = 1/3.

3. 3 1/5 * 5/8 : 2/7 = 7;

1) 3 1/5 * 5/8 = (3 * 5 + 1)/5 * 5/8 = (15 + 1)/5 * 5/8 = 16/5 * 5/8 = (16 * 5)/(5 * 8) = (2 * 8 * 5)/(5 * 8) = 2;

2) 2 : 2/7 = 2 * 7/2 = (2 * 7)/2 = 7.