33. Найдите значение выражения: а) \(12\frac{2}{5}-2\frac{2}{7}:1\frac{19}{21}\); б) \((12\frac{2}{5}-2\frac{2}{7}):1\frac{19}{21}\).

а) Сначала выполняем деление:

\(2\frac{2}{7}=\frac{16}{7}\), \(1\frac{19}{21}=\frac{40}{21}\).

\(\frac{16}{7}:\frac{40}{21}=\frac{16}{7}\cdot\frac{21}{40}=\frac{6}{5}\).

\(12\frac{2}{5}-\frac{6}{5}=\frac{62}{5}-\frac{6}{5}=\frac{56}{5}=11\frac{1}{5}\).

Ответ: \(11\frac{1}{5}\).

б) \(12\frac{2}{5}-2\frac{2}{7}=\frac{62}{5}-\frac{16}{7}=\frac{354}{35}\).

\(\frac{354}{35}:\frac{40}{21}=\frac{354}{35}\cdot\frac{21}{40}=\frac{531}{100}=5\frac{31}{100}\).

Ответ: \(5\frac{31}{100}\).