Решим данное выражение по действиям:
- $$15-12\frac{5}{8} = 15 - \frac{101}{8} = \frac{15 \cdot 8}{8} - \frac{101}{8} = \frac{120}{8} - \frac{101}{8} = \frac{19}{8} = 2\frac{3}{8}$$
- $$13\frac{1}{2} - 11\frac{2}{9} = \frac{27}{2} - \frac{101}{9} = \frac{27 \cdot 9}{2 \cdot 9} - \frac{101 \cdot 2}{9 \cdot 2} = \frac{243}{18} - \frac{202}{18} = \frac{41}{18} = 2\frac{5}{18}$$
- $$2\frac{3}{8} - 2\frac{5}{18} = \frac{19}{8} - \frac{41}{18} = \frac{19 \cdot 9}{8 \cdot 9} - \frac{41 \cdot 4}{18 \cdot 4} = \frac{171}{72} - \frac{164}{72} = \frac{7}{72}$$
Ответ: $$\frac{7}{72}$$