$\mathrm{2,5}\cdot \mathrm{0,25}=\mathrm{0,625}2\{,\}5\backslash cdot0\{,\}25=0\{,\}625$

$\mathrm{1,6}+\mathrm{0,4}\cdot 5=\mathrm{1,6}+2=\mathrm{3,6}1\{,\}6+0\{,\}4\cdot 5=1\{,\}6+2=3\{,\}6$

$-5+(-2)-(-4)=-5-2+4=-3-5+(-2)-(-4)=-5-2+4=-3$

${\displaystyle \frac{5}{4}}-{\displaystyle \frac{1}{2}}={\displaystyle \frac{5}{4}}-{\displaystyle \frac{2}{4}}={\displaystyle \frac{3}{4}}\backslash dfrac54-\backslash dfrac12=\backslash dfrac54-\backslash dfrac24=\backslash dfrac34$