7) 17+25=

$$\frac{17}{24}+\frac{25}{36} = \frac{17 \cdot 3}{24 \cdot 3} + \frac{25 \cdot 2}{36 \cdot 2} = \frac{51}{72}+\frac{50}{72} = \frac{101}{72} = 1\frac{29}{72}$$

Ответ: $$1\frac{29}{72}$$