Ответ:
а) \( \frac49\cdot\left(-\frac38\right)=-\frac{12}{72}=-\frac16 \).
б) \( \frac56-\frac49:\frac{16}{21}=\frac56-\frac49\cdot\frac{21}{16}=\frac56-\frac7{12}=\frac{10}{12}-\frac7{12}=\frac14 \).
Ответ: а) \(-\frac16\); б) \(\frac14\).
а) \( \frac49\cdot\left(-\frac38\right)=-\frac{12}{72}=-\frac16 \).
б) \( \frac56-\frac49:\frac{16}{21}=\frac56-\frac49\cdot\frac{21}{16}=\frac56-\frac7{12}=\frac{10}{12}-\frac7{12}=\frac14 \).
Ответ: а) \(-\frac16\); б) \(\frac14\).