Сократите дробь, используя признаки делимости: 1) 14/21, 18/24, 24/15, 25/35, 81/108; 2) 12/51, 4/26, 10/90, 35/45, 15/93; 3) 30/42, 33/39, 45/51, 36/60, 50/100; 4) 15/95, 33/48, 63/108, 34/82, 105/200.

Сократим каждую дробь, разделив числитель и знаменатель на их общий делитель.

1. \(\frac{14}{21}=\frac{2}{3}\), \(\frac{18}{24}=\frac{3}{4}\), \(\frac{24}{15}=\frac{8}{5}\), \(\frac{25}{35}=\frac{5}{7}\), \(\frac{81}{108}=\frac{3}{4}\).
2. \(\frac{12}{51}=\frac{4}{17}\), \(\frac{4}{26}=\frac{2}{13}\), \(\frac{10}{90}=\frac{1}{9}\), \(\frac{35}{45}=\frac{7}{9}\), \(\frac{15}{93}=\frac{5}{31}\).
3. \(\frac{30}{42}=\frac{5}{7}\), \(\frac{33}{39}=\frac{11}{13}\), \(\frac{45}{51}=\frac{15}{17}\), \(\frac{36}{60}=\frac{3}{5}\), \(\frac{50}{100}=\frac{1}{2}\).
4. \(\frac{15}{95}=\frac{3}{19}\), \(\frac{33}{48}=\frac{11}{16}\), \(\frac{63}{108}=\frac{7}{12}\), \(\frac{34}{82}=\frac{17}{41}\), \(\frac{105}{200}=\frac{21}{40}\).

Ответ: 1) \(\frac{2}{3};\frac{3}{4};\frac{8}{5};\frac{5}{7};\frac{3}{4}\). 2) \(\frac{4}{17};\frac{2}{13};\frac{1}{9};\frac{7}{9};\frac{5}{31}\). 3) \(\frac{5}{7};\frac{11}{13};\frac{15}{17};\frac{3}{5};\frac{1}{2}\). 4) \(\frac{3}{19};\frac{11}{16};\frac{7}{12};\frac{17}{41};\frac{21}{40}\).