31. Сократите дроби: 12/68, 6/10, 33/45, 4/16; 4/20, 90/150, 520/65, 123/123; 4/6, 20/50, 40/118, 20/18; 9/120, 48/102, 124/24, 540/20.

Сокращаем каждую дробь на наибольший общий делитель числителя и знаменателя.

1. \(\frac{12}{68}=\frac{3}{17}\); \(\frac{6}{10}=\frac{3}{5}\); \(\frac{33}{45}=\frac{11}{15}\); \(\frac{4}{16}=\frac{1}{4}\).
2. \(\frac{4}{20}=\frac{1}{5}\); \(\frac{90}{150}=\frac{3}{5}\); \(\frac{520}{65}=8\); \(\frac{123}{123}=1\).
3. \(\frac{4}{6}=\frac{2}{3}\); \(\frac{20}{50}=\frac{2}{5}\); \(\frac{40}{118}=\frac{20}{59}\); \(\frac{20}{18}=\frac{10}{9}\).
4. \(\frac{9}{120}=\frac{3}{40}\); \(\frac{48}{102}=\frac{8}{17}\); \(\frac{124}{24}=\frac{31}{6}\); \(\frac{540}{20}=27\).