答案：解析：
这些问题都是关于分数的加减运算，而且每个问题的分母都是相同的，所以只需要对分子进行加减就可以了。
答案：
1. $\frac{3}{8} + \frac{5}{8} = 1$
2. $\frac{4}{9} + \frac{1}{9} = \frac{5}{9}$
3. $\frac{2}{6} + \frac{3}{6} = \frac{5}{6}$
4. $\frac{7}{5} + \frac{2}{5} = \frac{9}{5}$
5. $\frac{3}{16} + \frac{4}{16} = \frac{7}{16}$
6. $\frac{5}{11} - \frac{2}{11} = \frac{3}{11}$
7. $\frac{8}{15} - \frac{1}{15} = \frac{7}{15}$
8. $\frac{5}{12} + \frac{5}{12} = \frac{10}{12} = \frac{5}{6}$
9. $\frac{3}{7} + \frac{3}{7} = \frac{6}{7}$
10. $\frac{4}{11} + \frac{4}{11} = \frac{8}{11}$
11. $\frac{5}{8} + \frac{5}{8} = \frac{10}{8} = \frac{5}{4}$
12. $\frac{6}{13} + \frac{6}{13} = \frac{12}{13}$
13. $\frac{1}{3} + \frac{1}{3} + \frac{1}{3} = 1$
14. $\frac{2}{5} + \frac{2}{5} + \frac{2}{5} = \frac{6}{5}$
15. $\frac{3}{7} + \frac{3}{7} + \frac{3}{7} = \frac{9}{7}$
16. $\frac{3}{8} + \frac{3}{8} + \frac{3}{8} = \frac{9}{8}$
17. $\frac{3}{10} + \frac{3}{10} + \frac{3}{10} = \frac{9}{10}$
18. $\frac{7}{20} + \frac{7}{20} + \frac{7}{20} = \frac{21}{20}$
19. $\frac{5}{7} + \frac{5}{7} + \frac{5}{7} + \frac{5}{7} = \frac{20}{7}$
20. $\frac{2}{9} + \frac{2}{9} + \frac{2}{9} + \frac{2}{9} = \frac{8}{9}$
21. $\frac{4}{15} + \frac{4}{15} + \frac{4}{15} + \frac{4}{15} = \frac{16}{15}$
22. $\frac{7}{12} + \frac{7}{12} + \frac{7}{12} + \frac{7}{12} + \frac{7}{12} = \frac{35}{12}$
23. $\frac{9}{11} + \frac{9}{11} + \frac{9}{11} + \frac{9}{11} + \frac{9}{11} = \frac{45}{11}$
24. $\frac{4}{9} + \frac{4}{9} + \frac{4}{9} + \frac{4}{9} + \frac{4}{9} = \frac{20}{9}$