5. Вычислите: 1) 2 · 1/4 + 3/7 − 9/4; 2) 12/13 + 4/10 · 3/2 − 1 3/8; 3) 1/5 + 3/2 : 4/5 − 2/7; 4) (7 − 4/7 : 16/32) − 12/14 · 6/8.

1. \(2\cdot\frac14+\frac37-\frac94=\frac12+\frac37-\frac94=\frac{14+12-63}{28}=-\frac{37}{28}=-1\frac9{28}\).
2. \(\frac{12}{13}+\frac4{10}\cdot\frac32-1\frac38=\frac{12}{13}+\frac25\cdot\frac32-\frac{11}{8}=\frac{12}{13}+\frac35-\frac{11}{8}=\frac{77}{520}\).
3. \(\frac15+\frac32:\frac45-\frac27=\frac15+\frac32\cdot\frac54-\frac27=\frac15+\frac{15}{8}-\frac27=\frac{501}{280}=1\frac{221}{280}\).
4. \(\left(7-\frac47:\frac{16}{32}\right)-\frac{12}{14}\cdot\frac68=\left(7-\frac47:\frac12\right)-\frac67\cdot\frac34=\left(7-\frac87\right)-\frac9{14}=\frac{73}{14}=5\frac3{14}\).

Ответ: 1) \(-1\frac9{28}\); 2) \(\frac{77}{520}\); 3) \(1\frac{221}{280}\); 4) \(5\frac3{14}\).