Помогите! Дам 30 баллов!!

1) $13 \frac{2}{5} - \frac{56}{5} *\frac{3}{28} =13 \frac{2}{5} - \frac{6}{5} =12 \frac{1}{5}$

2) $3,6+4,8(7 \frac{21}{12} -7 \frac{10}{12} )=3,6+ \frac{24}{5} *\frac{11}{12}=3,6+4,4=8$

3) $\frac{5}{12} a+ \frac{9}{12} a- \frac{6}{12} a= \frac{8}{12} a= \frac{2}{3} a= \frac{2}{3} * \frac{21}{10} =1,4$

4) $x = \frac{1,3*0,6}{3,9} = \frac{0,6}{3} =0,2$

5) $l = 2 \pi r=2*2,2*3,14 = 13,816$ см