Сравнить значения выражений 1\2+1\3и1\2+1\9;0,8и1\3+1\5 решение

$\displaystyle \frac{1}{2}+ \frac{1}{3}= \frac{3}{6}+ \frac{2}{6}= \frac{5}{6}= \frac{15}{18} \\ \\ \frac{1}{2}+ \frac{1}{9}= \frac{9}{18}+ \frac{2}{18}= \frac{11}{18} \\ \\ \frac{15}{18}\ \textgreater \ \frac{11}{18}=\ \textgreater \ \frac{1}{2}+ \frac{1}{3}\ \textgreater \ \frac{1}{2}+ \frac{1}{9}$

Или так:

$\displaystyle \frac{1}{2}+ \frac{1}{3}= \frac{1}{2}+ \frac{3}{9} \\ \\ \frac{1}{2}+ \frac{3}{9}\ \textgreater \ \frac{1}{2}+ \frac{1}{9}=\ \textgreater \ \frac{1}{2}+ \frac{1}{3}\ \textgreater \ \frac{1}{2}+ \frac{1}{9}$

$\displaystyle 0,8= \frac{8}{10} \\ \\\frac{1}{3}+ \frac{1}{5}= \frac{5}{15}+ \frac{3}{15}= \frac{8}{15} \\ \\ \frac{8}{10}\ \textgreater \ \frac{8}{15}=\ \textgreater \ 0,8\ \textgreater \ \frac{1}{3}+ \frac{1}{5}$