алгебра 7 класс задания 5
[tex](5 \frac{8}{9} \div 1 \frac{17}{36} + 1 \frac{1}{4} ) \times \frac{5}{21 } [/tex]

(53/9:53/36+ 5/4)*5/21= (53/9*36/53+5/4)*5/21= (4+5/4)*5/21= 21/4*5/21= 5/4= 1 1/4 ( или 1,25)