Ответ:

1. 1/4

Пошаговое объяснение:

1) 6,25 : 5/3 = 6. 25/100 : 5/3 = 625/100 * 3/5 = 125/100 * 3/1 = 375/100 = 3. 75/100 = 3. 3/4

2) 2,5 : 1,5 = 25/10 : 15/10 = 25/10 * 10/15 = 5/1 * 1/3 = = 5/3 = 1. 2/3

3) 3. 3/4 - 1. 2/3 = 3. 9/12 - 1. 8/12 = 2. 1/12

4) 2. 1/12 + 7. 1/2 = 2. 1/12 + 7. 6/12 = 9. 7/12

5) 9. 7/12 - 8. 1/3 = 9. 7/12 - 8. 4/12 = 1. 3/12 = 1. 1/4