Question

Найди значений выражений 7 4/5-2 7/15

Answer 1

Решение и ответ:

1 способ

$\displaystyle 7\frac{4}{5}-2\frac{7}{{15}}=7\frac{{3\cdot 4}}{{3\cdot 5}}-2\frac{7}{{15}}=7\frac{{12}}{{15}}-2\frac{7}{{15}}=\left({7-2}\right)+\left({\frac{{12}}{{15}}-\frac{7}{{15}}}\right)=5+\left({\frac{{12-7}}{{15}}}\right)=5+\frac{5}{{15}}=5+\frac{1}{3}=\boxed{5\frac{1}{3}}$

2 способ

$\displaystyle 7\frac{4}{5}-2\frac{7}{{15}}=\frac{{39}}{5}-\frac{{37}}{{15}}=\frac{{3\cdot 39}}{{3\cdot 5}}-\frac{{37}}{{15}}=\frac{{117}}{{15}}-\frac{{37}}{{15}}=\frac{{80}}{{15}}=\frac{{\textbf{5}\cdot 16}}{{\textbf{5}\cdot 3}}=\frac{{16}}{3}=\boxed{5\frac{1}{3}}$