Problems from Absolute value of a real number

$|-0.75|=max(0.75,-0.75)=0.75$

$|{\displaystyle \frac{1}{5}}-{\displaystyle \frac{1}{3}}|=|{\displaystyle \frac{3-5}{15}}|=|{\displaystyle \frac{-2}{15}}|={\displaystyle \frac{2}{15}}$

$|{\displaystyle \frac{1}{2}}-{\displaystyle \frac{2}{3}}+{\displaystyle \frac{1}{5}}|=|{\displaystyle \frac{15-20+6}{30}}|=|{\displaystyle \frac{1}{30}}|={\displaystyle \frac{1}{30}}$

$0,6={\displaystyle \frac{6}{10}}={\displaystyle \frac{3}{5}}$, and to be able to compare both fractions, we do ${\displaystyle \frac{3}{5}}={\displaystyle \frac{18}{30}}$, then it is easy to see that ${\displaystyle \frac{1}{30}}<{\displaystyle \frac{18}{30}}$