4 Приведите дроби к общему знаменателю: а) \(\frac{1}{2}\) и \(\frac{1}{3}\); б) \(\frac{3}{4}\) и \(\frac{7}{8}\); в) \(\frac{7}{10}\) и \(\frac{8}{15}\); г) \(\frac{4}{21}\) и \(\frac{2}{7}\)

1. а) \(\frac{1}{2}\) и \(\frac{1}{3}\)
   • НОЗ(2, 3) = 6
   • \(\frac{1}{2} = \frac{1 \cdot 3}{2 \cdot 3} = \frac{3}{6}\)
   • \(\frac{1}{3} = \frac{1 \cdot 2}{3 \cdot 2} = \frac{2}{6}\)
2. б) \(\frac{3}{4}\) и \(\frac{7}{8}\)
   • НОЗ(4, 8) = 8
   • \(\frac{3}{4} = \frac{3 \cdot 2}{4 \cdot 2} = \frac{6}{8}\)
   • \(\frac{7}{8}\) (остается без изменений)
3. в) \(\frac{7}{10}\) и \(\frac{8}{15}\)
   • НОЗ(10, 15) = 30
   • \(\frac{7}{10} = \frac{7 \cdot 3}{10 \cdot 3} = \frac{21}{30}\)
   • \(\frac{8}{15} = \frac{8 \cdot 2}{15 \cdot 2} = \frac{16}{30}\)
4. г) \(\frac{4}{21}\) и \(\frac{2}{7}\)
   • НОЗ(21, 7) = 21
   • \(\frac{4}{21}\) (остается без изменений)
   • \(\frac{2}{7} = \frac{2 \cdot 3}{7 \cdot 3} = \frac{6}{21}\)

Ответ: а) \(\frac{3}{6}\) и \(\frac{2}{6}\); б) \(\frac{6}{8}\) и \(\frac{7}{8}\); в) \(\frac{21}{30}\) и \(\frac{16}{30}\); г) \(\frac{4}{21}\) и \(\frac{6}{21}\)