Ответ:

а) \(1\frac{5}{19}=\frac{24}{19}\), а \(6-3\frac{5}{8}=\frac{51}{8}\).

\(\frac{24}{19}\cdot\frac{51}{8}=\frac{3\cdot51}{19}=\frac{153}{19}=8\frac{1}{19}\).

б) \(6,3:1,4=4,5\).

\((4,5-2,05)\cdot1,8=2,45\cdot1,8=4,41\).

Ответ: а) \(8\frac{1}{19}\); б) \(4,41\).