1)5 7/10 - 4 6/35 = 57/10 - 146/35 = (57 × 7 - 146 × 2)/70 = (399 - 292)/70 = 107/70 = 1 37/70
2) 23,1 ÷ 1 37/70 = 23 1/10 ÷ 1 37/70 = 231/10 ÷ 107/70 = 231/10 × 70/107 = 1617/107 = 15 12/107
3) 30 - 15 12/107 = 30 - 1617/107 =(30 × 107 - 1617 × 1)/107 = (3210 - 1617)/107 = 1593/107 = 14 95/107
ОТВЕТ : 14 95/107