а) \(\frac{2}{5}\cdot\frac{2}{5}=\frac{2\cdot2}{5\cdot5}=\frac{4}{25}\).
б) \(\frac{1}{3}\cdot\frac{1}{2}=\frac{1\cdot1}{3\cdot2}=\frac{1}{6}\).
Ответ: а) \(\frac{4}{25}\); б) \(\frac{1}{6}\).