a) \(\frac{3}{14} + \frac{1}{28}\) = \(\frac{3 \cdot 2}{14 \cdot 2} + \frac{1}{28}\) = \(\frac{6}{28} + \frac{1}{28}\) = \(\frac{6+1}{28}\) = \(\frac{7}{28}\) = \(\frac{7 \div 7}{28 \div 7}\) = \(\frac{1}{4}\)
Ответ: \(\frac{1}{4}\)