1) 7$$\frac{1}{5}$$:18$$\cdot$$2; 2) 2$$\frac{1}{16}$$\cdot24:11; 3) $$\frac{16}{25}$$\cdot20:24; 4) $$\frac{21}{40}$$\cdot8:28;

Решение:

1. 7$$\frac{1}{5}$$:18$$\cdot$$2 = $$\frac{36}{5}$$\cdot$$\frac{1}{18}$$\cdot$$2 = $$\frac{2}{5}$$\cdot$$2 = $$\frac{4}{5}$$
2. 2$$\frac{1}{16}$$\cdot24:11 = $$\frac{33}{16}$$\cdot$$\frac{24}{11}$$ = $$\frac{3}{2}$$\cdot$$3 = $$\frac{9}{2}$$ = 4$$\frac{1}{2}$$
3. $$\frac{16}{25}$$\cdot$$20:24 = $$\frac{16}{25}$$\cdot$$\frac{20}{24}$$ = $$\frac{2}{5}$$\cdot$$\frac{5}{3}$$ = $$\frac{2}{3}$$
4. $$\frac{21}{40}$$\cdot$$8:28 = $$\frac{21}{40}$$\cdot$$\frac{8}{28}$$ = $$\frac{3}{5}$$\cdot$$\frac{1}{4}$$ = $$\frac{3}{5}$$\cdot$$\frac{1}{4}$$ = $$\frac{3}{20}$$

Ответ:

1. $$\frac{4}{5}$$
2. 4$$\frac{1}{2}$$
3. $$\frac{2}{3}$$
4. $$\frac{3}{20}$$