1) Сократите дроби: 12/60; 42/63; 56/72; 35/80.

1. \(\frac{12}{60}=\frac{12:12}{60:12}=\frac{1}{5}\).
2. \(\frac{42}{63}=\frac{42:21}{63:21}=\frac{2}{3}\).
3. \(\frac{56}{72}=\frac{56:8}{72:8}=\frac{7}{9}\).
4. \(\frac{35}{80}=\frac{35:5}{80:5}=\frac{7}{16}\).

Ответ: \(\frac{1}{5};\ \frac{2}{3};\ \frac{7}{9};\ \frac{7}{16}\).