Ответ:
а)
\(1\frac{5}{17}=\frac{22}{17}\), \(2\frac{4}{11}=\frac{26}{11}\).
\(7-\frac{26}{11}=\frac{77}{11}-\frac{26}{11}=\frac{51}{11}\).
\(\frac{22}{17}\cdot\frac{51}{11}=\frac{2\cdot51}{17}=\frac{102}{17}=6\).
б)
\(42:12=3,5\), \(1,05:1,6=\frac{105}{160}=\frac{21}{32}=0,65625\).
\(3,5-0,65625=2,84375\).
Ответ: а) 6; б) 2,84375.
