1) 2 целых 13/16 : 4 целых 3/8 = 45/16 ÷ 35/8 = 45/16 × 8/35 = (45 × 8)/(16 × 35) = (9 × 1)/(2 × 7) = 9/14
2) 3 целых 1/3 : 2 целых 6/7 = 10/3 ÷ 20/7 = 10/3 × 7/20 = (10 × 7)/(3 × 20) = 7/(3 ×2) = 7/6 = 1 целая 1/6
3) 3 целых 6/7 : 9/28 = 27/7 ÷ 9/28 = 27/7 × 28/9 = (27 × 28)/(7 × 9) = (3 × 4)/(1 × 1) = 12/1 = 12