18) 1 6/40 · 1 23/33 =

\(1\frac{6}{40}=\frac{23}{20}\), \(1\frac{23}{33}=\frac{56}{33}\).

\(\frac{23}{20}\cdot\frac{56}{33}=\frac{322}{165}=1\frac{157}{165}\).

Ответ: 1\(\frac{157}{165}\)