1) $$2\frac{1}{3}\cdot9-1\frac{1}{3}\cdot3\frac{1}{4}-2\frac{2}{7}\cdot3\frac{5}{24}$$

Решим пример по действиям:

1. $$2\frac{1}{3}\cdot9 = \frac{7}{3}\cdot9 = \frac{7\cdot9}{3} = \frac{7\cdot3}{1}=21$$
2. $$1\frac{1}{3}\cdot3\frac{1}{4} = \frac{4}{3}\cdot\frac{13}{4} = \frac{4\cdot13}{3\cdot4} = \frac{13}{3} = 4\frac{1}{3}$$
3. $$2\frac{2}{7}\cdot3\frac{5}{24} = \frac{16}{7}\cdot\frac{77}{24} = \frac{16\cdot77}{7\cdot24} = \frac{2\cdot11}{1\cdot3} = \frac{22}{3} = 7\frac{1}{3}$$
4. $$21 - 4\frac{1}{3} = 20\frac{3}{3}-4\frac{1}{3} = (20-4) + (\frac{3}{3}-\frac{1}{3}) = 16+\frac{2}{3} = 16\frac{2}{3}$$
5. $$16\frac{2}{3}-7\frac{1}{3} = (16-7) + (\frac{2}{3}-\frac{1}{3}) = 9 + \frac{1}{3} = 9\frac{1}{3}$$

Ответ: $$9\frac{1}{3}$$