Ответ:

а) \(1\frac{5}{19}=\frac{24}{19}\), \(6-3\frac{5}{8}=\frac{48}{8}-\frac{29}{8}=\frac{19}{8}\).

\(\frac{24}{19}\cdot\frac{19}{8}=3\).

б) \(6,3:1,4=4,5\).

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

Ответ: а) 3; б) 4,41.