Вычислите: 1 1/3*3 1/4; 3/4*1 1/3; 2/11*1 5/6; 5 5/7*9/20

Решите задачу:

$1\frac{1}{3} * 3\frac{1}{4} = \frac{4}{3} * \frac{13}{4} = \frac{4*13}{3*4} =$ $\frac{13}{3} = 4 \frac{1}{3}$

$\frac{3}{4} * 1\frac{1}{3} = \frac{3}{4} * \frac{4}{3} = \frac{3*4}{4*3} =1$

$\frac{2}{11} * 1\frac{5}{6} = \frac{2}{11}* \frac{11}{6} = \frac{2*11}{11*6} = \frac{2}{6} = \frac{1}{3}$

$5\frac{5}{7} * \frac{9}{20} = \frac{40}{7} * \frac{9}{20} = \frac{40*9}{7*20} = \frac{2*9}{7*1} = \frac{18}{7} = 2 \frac{4}{7}$