(2 4/5 + 2 2/3): (10 13/30-3,6)*1,25 подробно

1) 2 4/5  +  2 2/3 = 14/5  +  8/3 = (14 × 3  +  8 × 5)/15 = 42/15  +  40/15 =  82/15 = 5 7/15
2) 10 13/30 - 3,6 = 10 13/30 - 3 6/10 = 313/30 - 36/10 =313/30  -  18/5 =(313 × 1  -  18 × 6)/30 = 313/30  -  108/30 =  205/30 = 41/6 = 6 5/6
3) 5 7/15 ÷ 6 5/6 = 82/15  ÷  41/6 = 82/15  ×  6/41 =  4/5 = 0,8
4) 0,8 * 1,25 = 1
ОТВЕТ : 1