Вычислите: а) 3/14 + 1/28; б) 4/15 − 3/25; в) 5/16 + 4/63.

1. \(\frac{3}{14}+\frac{1}{28}=\frac{6}{28}+\frac{1}{28}=\frac{7}{28}=\frac{1}{4}\).
2. \(\frac{4}{15}-\frac{3}{25}=\frac{20}{75}-\frac{9}{75}=\frac{11}{75}\).
3. \(\frac{5}{16}+\frac{4}{63}=\frac{315}{1008}+\frac{64}{1008}=\frac{379}{1008}\).

Ответ: а) \(\frac{1}{4}\); б) \(\frac{11}{75}\); в) \(\frac{379}{1008}\).