Решите действие с обыкновенными дробями: 2/5+2 4/9:((7 5/12-5 3/4):22 1/2+10*5/18)-4/5=?

Решите задачу:

$\frac{2}{5} +2 \frac{4}{9} :((7 \frac{5}{12} -5 \frac{3}{4} ):22 \frac{1}{2}+10* \frac{5}{18} )- \frac{4}{5} \\ 1)7 \frac{5}{12} -5 \frac{3}{4} = \frac{89}{12} - \frac{23}{4} = \frac{89-69}{12} = \frac{20}{12}= \frac{5}{3} \\ 2) \frac{5}{3} :22 \frac{1}{2}= \frac{5}{3} : \frac{45}{2} = \frac{5*2}{3*45}= \frac{2}{27} \\ 3) 10* \frac{5}{18}= \frac{25}{9}\\ 4) \frac{2}{27} +\frac{25}{9}= \frac{2+75}{27} = \frac{77}{27} \\ 5)2 \frac{4}{9} :\frac{77}{27}= \frac{22}{9} :\frac{77}{27}= \frac{22*27}{9*77}= 66/77$
$6) \frac{2}{5}+ \frac{66}{77} = \frac{154+330}{385} = \frac{484}{385}\\ 7) \frac{484}{385}- \frac{4}{5} = \frac{484-308}{385} = \frac{176}{385}$