Помогите решить примеры по математике

Решите задачу:

$3\frac{1}{9}: 2\frac{1}{3}: 6\frac{3}{4}* \frac{9}{16}= \frac{28}{9}:\frac{7}{3}: \frac{27}{4}* \frac{9}{16}= \frac{28}{9}* \frac{3}{7}* \frac{4}{27} * \frac{9}{16}= \frac{28*3*4*9}{9*7*27*16} = \\ = \frac{4*7*3*4*9}{9*7*3*9*4*4} = \frac{1}{9}$

$4:4 \frac{4}{5} +2 \frac{2}{7} *5 \frac{1}{4} -7 \frac{11}{12} = 4 \frac{11}{12} \\ \\ 1)4:4 \frac{4}{5}=4: \frac{24}{5}= \frac{4}{1} * \frac{5}{24} = \frac{4}{1}* \frac{5}{6*4}= \frac{5}{6} ; \\ 2)2 \frac{2}{7} *5 \frac{1}{4}=\frac{16}{7} * \frac{21}{4}=\frac{4*4}{7} * \frac{7*3}{4}=12; \\ 3)\frac{5}{6} +12=12\frac{5}{6} ; \\ 4)12\frac{5}{6}-7 \frac{11}{12}=12\frac{10}{12}-7 \frac{11}{12}=11\frac{22}{12}-7 \frac{11}{12}=4 \frac{11}{12} .$

$(3 \frac{3}{8}- \frac{1}{4} ):4 \frac{1}{6} *1 \frac{7}{9} =1 \frac{1}{3} \\ \\ 1)3 \frac{3}{8}- \frac{1}{4} =3 \frac{3}{8}- \frac{2}{8} =3 \frac{1}{8} ; \\ 2)3 \frac{1}{8}:4 \frac{1}{6}= \frac{25}{8}: \frac{25}{6}= \frac{25}{8}*\frac{6}{25}= \frac{3}{4} ; \\ 3) \frac{3}{4}*1 \frac{7}{9} = \frac{3}{4}* \frac{16}{9}= \frac{4}{3} =1 \frac{1}{3}.$