Ответ:
- 1/4 + 3/5 = 5/20 + 12/20 = 17/20.
- 13 − 3 13/25 = 12 25/25 − 3 13/25 = 9 12/25.
- 7 1/3 + 2 18/27 = 7 1/3 + 2 2/3 = 10.
- 9 4/21 − 4 11/14 = 193/21 − 67/14 = 386/42 − 201/42 = 4 17/42.
- 7/15 × 45/49 = 3/7 × 3 = 1 2/7.
- 3/5 × 1 5/6 = 3/5 × 11/6 = 1 1/10.
- 6 : 3/4 = 6 × 4/3 = 8.
- 3 1/2 : 2 5/8 = 7/2 × 8/21 = 1 1/3.
