4 2/3- 5/9* 2 4/7 ----------------------------- +0,8*1,25 (2 1/7+1 2/3):5

Выражением:
$\frac{4 \frac{2}{3} - \frac{5}{9} *2 \frac{4}{7} }{ (2\frac{1}{7} +1 \frac{2}{3}):5 } + 0,8*1,25= \frac{ \frac{14}{3}- \frac{5*18}{9*7} }{(2 \frac{3}{21} + 1 \frac{14}{21} ) * \frac{1}{5} } + 1= \\ \\ =\frac{ \frac{98}{21}- \frac{30}{21} }{\frac{80*1}{21*5}} +1= \frac{ \frac{68}{21} }{ \frac{80}{21*5} }+1 = \frac{68*21*5}{80*21}+1= \\ \\ = \frac{17*5}{20*1} +1 = \frac{17}{4} +1= 4 \frac{1}{4}+1 = 5 \frac{1}{4} = 5,25$