Решим уравнения:
- a) $$12 - x = 1\frac{3}{9}$$
$$12 - x = 1\frac{1}{3}$$
$$x = 12 - 1\frac{1}{3}$$
$$x = 11\frac{3}{3} - \frac{1}{3}$$
$$x = 11\frac{2}{3}$$
- в) $$5\frac{8}{9} + x = 7\frac{1}{18}$$
$$x = 7\frac{1}{18} - 5\frac{8}{9}$$
$$x = 7\frac{1}{18} - 5\frac{8 \times 2}{9 \times 2}$$
$$x = 7\frac{1}{18} - 5\frac{16}{18}$$
$$x = 6\frac{19}{18} - 5\frac{16}{18}$$
$$x = 1\frac{3}{18}$$
$$x = 1\frac{1}{6}$$
Ответ: a) $$11\frac{2}{3}$$, в) $$1\frac{1}{6}$$