Решение:

1. $$\frac{24}{37} + \frac{8}{37} - \frac{11}{37} = \frac{24 + 8 - 11}{37} = \frac{32 - 11}{37} = \frac{21}{37}$$

   Ответ: $$\frac{21}{37}$$

2. $$3\frac{7}{11} + 6\frac{3}{11} - 5\frac{5}{11} = (3 + 6 - 5) + (\frac{7}{11} + \frac{3}{11} - \frac{5}{11}) = 4 + \frac{7 + 3 - 5}{11} = 4 + \frac{5}{11} = 4\frac{5}{11}$$

   Ответ: $$4\frac{5}{11}$$

3. $$5\frac{3}{8} - 2\frac{5}{8} = 5\frac{3}{8} - 2\frac{5}{8} = \frac{5 \cdot 8 + 3}{8} - \frac{2 \cdot 8 + 5}{8} = \frac{40 + 3}{8} - \frac{16 + 5}{8} = \frac{43}{8} - \frac{21}{8} = \frac{43 - 21}{8} = \frac{22}{8} = \frac{11}{4} = 2\frac{3}{4}$$

   Ответ: $$2\frac{3}{4}$$