20:2 2/15+25 5/7:1 1/35

20 : 2 2/15 + 25 5/7 : 1 1/35 = 34 целых 3/81) 20 : 2 2/15 = 20 : 32/15 = 20/1 * 15/32 = (5*15)/(1*8) = 75/8 = 9 3/82) 25 5/7 : 1 1/35 = 180/7 : 36/35 = 180/7 * 35/36 = (5*5)/(1*1) = 253) 9 3/8 + 25 = 34 3/8Пояснения:2 целых 2/15 = (2*15+2)/15 = 32/1525 целых 5/7 = (25*7+5)/7 = 180/71 целая 1/35 = (1*35+1)/35 = 36/35