Ответ:

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

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

  2. Сначала вычислим выражение в скобках:

    \(6{,}3\cdot1{,}4=8{,}82\),

    \(8{,}82-2{,}05=6{,}77\).

    \(1{,}8\cdot6{,}77=12{,}186\).

  3. \(1\frac{2}{23}=\frac{25}{23}\), \(2{,}07=\frac{207}{100}\).

    \(\frac{25}{23}\cdot\frac{207}{100}\cdot\frac{2}{9}=\frac{1}{2}\).

  4. \(3{,}2=\frac{16}{5}\), \(2\frac{5}{8}=\frac{21}{8}\).

    \(\frac{16}{5}\cdot\frac{21}{8}\cdot\frac{5}{7}\cdot\frac{16}{5}=\frac{96}{5}=19{,}2\).

  5. \(1\frac{5}{7}=\frac{12}{7}\), \(1\frac{2}{3}=\frac{5}{3}\), \(4{,}2=\frac{21}{5}\).

    \(\frac{12}{7}\cdot\frac{5}{3}\cdot\frac{21}{5}=12\).

  6. \(1{,}05=\frac{21}{20}\), \(1\frac{2}{3}=\frac{5}{3}\).

    \(\frac{8}{21}\cdot\frac{21}{20}\cdot\frac{5}{3}=\frac{2}{3}\).

Ответ: а) 3; б) 12,186; в) \(\frac{1}{2}\); г) 19,2; д) 12; е) \(\frac{2}{3}\).