1. 3/7 + 4/7 = ? 2. 7/9 - 1/9 = ? 3. 33/5 - 13/5 = ? 4. 9/12 + 5/12 = ?

Решаем примеры:

1. \[ \frac{3}{7} + \frac{4}{7} = \frac{3+4}{7} = \frac{7}{7} = 1 \]
2. \[ \frac{7}{9} - \frac{1}{9} = \frac{7-1}{9} = \frac{6}{9} = \frac{2}{3} \]
3. \[ \frac{33}{5} - \frac{13}{5} = \frac{33-13}{5} = \frac{20}{5} = 4 \]
4. \[ \frac{9}{12} + \frac{5}{12} = \frac{9+5}{12} = \frac{14}{12} = \frac{7}{6} \]

Ответ: 1, 2/3, 4, 7/6