Question

Надо. надо. ( 7целых -2 целых 2/5 *1 целую 7/8) : 5 целых 5/8=

Answer 1

(7 - 2 2/5 * 1 7/8) : 5 5/8 = 4/9

1) 2 2/5 * 1 7/8 = 12/5 * 15/8 = (3*3)/(1*2) = 9/2 = 4 1/2
2) 7 - 4 1/2 = 6 2/2 - 4 1/2 = 2 1/2
3) 2 1/2 : 5 5/8 = 5/2 : 45/8 = 5/2 * 8/45 = (1*4)/(1*9) = 4/9

Answer 2

$( 7- 2\frac{2}{5}*1 \frac{7}{8}):5 \frac{5}{8} = (7- \frac{12}{5}*\frac{15}{8}):5 \frac{5}{8}=(7-\frac{3}{1}*\frac{3}{2}):5\frac{5}{8} =(7-\frac{9}{2}):5\frac{5}{8}$ =
= $(7-\frac{9}{2}):5\frac{5}{8} = 2 \frac{1}{2}: 5\frac{5}{8}= \frac{5}{2}: \frac{45}{8} = \frac{5}{2}* \frac{8}{45}= \frac{1}{1}* \frac{4}{9}= \frac{4}{9}$