1. Вычислите: 1) $$2\frac{3}{5} \cdot 1\frac{9}{26}$$; 2) $$\frac{7}{19} \cdot 57$$; 3) $$2\frac{2}{5}:1\frac{1}{15}$$; 4) $$6:\frac{12}{13}$$; 5) $$\frac{6}{19}:2$$.

1) $$2\frac{3}{5} \cdot 1\frac{9}{26}$$ = $$\frac{13}{5} \cdot \frac{35}{26}$$ = $$\frac{13 \cdot 35}{5 \cdot 26}$$ = $$\frac{13 \cdot 5 \cdot 7}{5 \cdot 13 \cdot 2}$$ = $$\frac{7}{2}$$ = $$3\frac{1}{2}$$

2) $$\frac{7}{19} \cdot 57 = \frac{7 \cdot 57}{19} = \frac{7 \cdot 19 \cdot 3}{19} = 7 \cdot 3 = 21$$

3) $$2\frac{2}{5}:1\frac{1}{15} = \frac{12}{5} : \frac{16}{15} = \frac{12}{5} \cdot \frac{15}{16} = \frac{12 \cdot 15}{5 \cdot 16} = \frac{3 \cdot 4 \cdot 3 \cdot 5}{5 \cdot 4 \cdot 4} = \frac{9}{4} = 2\frac{1}{4}$$

4) $$6:\frac{12}{13} = 6 \cdot \frac{13}{12} = \frac{6 \cdot 13}{12} = \frac{13}{2} = 6\frac{1}{2}$$

5) $$\frac{6}{19}:2 = \frac{6}{19} \cdot \frac{1}{2} = \frac{6 \cdot 1}{19 \cdot 2} = \frac{3}{19}$$

Ответ: 1) $$3\frac{1}{2}$$; 2) $$21$$; 3) $$2\frac{1}{4}$$; 4) $$6\frac{1}{2}$$; 5) $$\frac{3}{19}$$