4. Сократите дроби: а) 14/21; 12/30; 24/60; 36/105; б) 55/77; 81/270; 75/450; 126/180; в) 140/210; 105/165; 144/360; 240/560; г) 30/150; 80/200; 21/36; 81/108.

Делим числитель и знаменатель каждой дроби на их наибольший общий делитель:

а) \(\frac{14}{21}=\frac{2}{3}\); \(\frac{12}{30}=\frac{2}{5}\); \(\frac{24}{60}=\frac{2}{5}\); \(\frac{36}{105}=\frac{12}{35}\).

б) \(\frac{55}{77}=\frac{5}{7}\); \(\frac{81}{270}=\frac{3}{10}\); \(\frac{75}{450}=\frac{1}{6}\); \(\frac{126}{180}=\frac{7}{10}\).

в) \(\frac{140}{210}=\frac{2}{3}\); \(\frac{105}{165}=\frac{7}{11}\); \(\frac{144}{360}=\frac{2}{5}\); \(\frac{240}{560}=\frac{3}{7}\).

г) \(\frac{30}{150}=\frac{1}{5}\); \(\frac{80}{200}=\frac{2}{5}\); \(\frac{21}{36}=\frac{7}{12}\); \(\frac{81}{108}=\frac{3}{4}\).