Решение:

a)

$$\frac{2}{3} + \frac{1}{6} = \frac{2 \cdot 2}{3 \cdot 2} + \frac{1}{6} = \frac{4}{6} + \frac{1}{6} = \frac{4+1}{6} = \frac{5}{6}$$

б)

$$12 - 9\frac{3}{7} = 12 - \frac{9 \cdot 7 + 3}{7} = 12 - \frac{63 + 3}{7} = 12 - \frac{66}{7} = \frac{12 \cdot 7}{7} - \frac{66}{7} = \frac{84 - 66}{7} = \frac{18}{7} = 2\frac{4}{7}$$

в)

$$1\frac{1}{3} \cdot 1\frac{1}{2} = \frac{1 \cdot 3 + 1}{3} \cdot \frac{1 \cdot 2 + 1}{2} = \frac{4}{3} \cdot \frac{3}{2} = \frac{4 \cdot 3}{3 \cdot 2} = \frac{12}{6} = 2$$

г)

$$36,12 : 12 = 36,12 / 12 = 3,01$$ Ответ: а) $$\frac{5}{6}$$; б) $$2\frac{4}{7}$$; в) 2; г) 3,01