6) \(\frac{3}{8} + \frac{1}{4} = \frac{3}{8} + \frac{2}{8} = \frac{5}{8}\)

Решение:

\(\frac{3}{8} + \frac{1}{4} = \frac{3}{8} + \frac{1 \cdot 2}{4 \cdot 2} = \frac{3}{8} + \frac{2}{8} = \frac{3+2}{8} = \frac{5}{8}\)

Ответ: \(\frac{5}{8}\)