4. Вычислите: |1 1/4| · |−4/7|.

\(\left|1\frac{1}{4}\right|=\frac{5}{4}\), \(\left|-\frac{4}{7}\right|=\frac{4}{7}\).

\(\frac{5}{4}\cdot\frac{4}{7}=\frac{5}{7}\).

Ответ: \(\frac{5}{7}\).