1) 2 целых 1/7 3 целых 1/9 = (2 + 1/7) (3 + 1/9) = 23 + 2(1/9) + 3(1/7) + (1/7)(1/9) = 6 + 2/9 + 3/7 + 1/63 = 6 + 2/9 + 27/63 + 1/63 = 6 + 2/9 + 28/63 = 6 + 2/9 + 4/9 = 6 + 6/9 = 6 + 2/3 = 6 2/3

2) 3/7 7/9 = (3/7) (7/9) = 21/63 = 1/3

3) 5/8 1 целую 13/15 2 целых 2/7 = (5/8) (1 + 13/15) (2 + 2/7) = (5/8) (15/15 + 13/15) (7/7 + 2/7) = (5/8) (28/15) (9/7) = 140/120 28/15 9/7 = 14/12 28/15 9/7 = 7/6 28/15 9/7 = 14/6 * 9/7 = 2 + 3/7 = 2 3/7

Итак, результаты умножения дробей и целых чисел:

1) 2 целых 1/7 3 целых 1/9 = 6 2/3
2) 3/7 7/9 = 1/3
3) 5/8 1 целую 13/15 2 целых 2/7 = 2 3/7