9 15.8-7 16 5 16

15. $$8\frac{9}{16}-7\frac{5}{16} = (8-7) + (\frac{9}{16} - \frac{5}{16}) = 1 + \frac{4}{16} = 1\frac{4}{16}$$.

Сократим дробь на 4:

$$1\frac{4}{16} = 1\frac{1}{4}$$.

Ответ: $$1\frac{1}{4}$$