Ответ:

Решение:

  1. \( \frac{1}{12} + \frac{3}{4} = \frac{1}{12} + \frac{9}{12} = \frac{10}{12} = \frac{5}{6} \)
  2. \( 2 \frac{1}{4} : 1 \frac{1}{6} = \frac{9}{4} : \frac{7}{6} = \frac{9}{4} \cdot \frac{6}{7} = \frac{54}{28} = \frac{27}{14} = 1 \frac{13}{14} \)
  3. \( 2 - 1 \frac{3}{7} = \frac{14}{7} - \frac{10}{7} = \frac{4}{7} \)
  4. \( 12 \cdot \frac{3}{4} = \frac{12 \cdot 3}{4} = \frac{36}{4} = 9 \)

Ответ: a) \( \frac{5}{6} \); б) \( 1 \frac{13}{14} \); в) \( \frac{4}{7} \); г) 9.