Question

3*(9\10+4\5)-1:7\8*77\80=
По действиям! Прошу, помогите!

Answer 1

$3*\bigg(\tt\displaystyle\frac{9}{10}+\frac{4}{5}\bigg)-1:\frac{7}{8}*\frac{77}{80}=4$

$1)~\tt\displaystyle\frac{9}{10}+\frac{4}{5}=\frac{9}{10}+\frac{4*2}{5*2}=\frac{9}{10}+\frac{8}{10}=\frac{17}{10}$

$2)~3*\tt\displaystyle\frac{17}{10}=\frac{3*17}{10}=\frac{51}{10}$

$3)~1:\tt\displaystyle\frac{7}{8}=1*\frac{8}{7}=\frac{8}{7}$

$4)~\tt\displaystyle\frac{8}{7}*\frac{77}{80}=\frac{8*77}{7*80}=\frac{\not8*\not7*11}{\not7*\not8*10}=\frac{11}{10}$

$5)~\tt\displaystyle\frac{51}{10}-\frac{11}{10}=\frac{40}{10}=4$