1 Выполните действия: a) 1/12 + 3/4; b) 2 - 1 3/7; в) 2 1/4 : 1 1/6; г) 12 3/4.

1. Выполнение действий:

• а)\[ \frac{1}{12} + \frac{3}{4} = \frac{1}{12} + \frac{3 \times 3}{4 \times 3} = \frac{1}{12} + \frac{9}{12} = \frac{1+9}{12} = \frac{10}{12} = \frac{5}{6} \]
• б)\[ 2 - 1\frac{3}{7} = 2 - \frac{10}{7} = \frac{2 \times 7}{7} - \frac{10}{7} = \frac{14-10}{7} = \frac{4}{7} \]
• в)\[ 2\frac{1}{4} : 1\frac{1}{6} = \frac{2 \times 4 + 1}{4} : \frac{1 \times 6 + 1}{6} = \frac{9}{4} : \frac{7}{6} = \frac{9}{4} \times \frac{6}{7} = \frac{9 \times 6}{4 \times 7} = \frac{54}{28} = \frac{27}{14} \]
• г)\[ 12 \times \frac{3}{4} = \frac{12}{1} \times \frac{3}{4} = \frac{12 \times 3}{1 \times 4} = \frac{36}{4} = 9 \]

Ответ: а) 5/6, б) 4/7, в) 27/14, г) 9