$\mathrm{10,5}-\mathrm{2,9}=\mathrm{7,6}10\{,\}5-2\{,\}9=\; 7\{,\}6$

$-(-1)+(-1+1)-1-(-\; 1)+(-1+1)\; -\; 1$

$=1+(0)-1=\; 1+(0)-1$

$=0=0$

$1\frac{4}{5}\cdot \frac{5}{2}=\frac{9}{5}\cdot \frac{5}{2}=\frac{9}{2}1\backslash \; \backslash frac\{4\}\{5\}\backslash cdot\backslash frac\{5\}\{2\}=\backslash frac\{9\}\{5\}\backslash cdot\backslash frac\{5\}\{2\}=\backslash frac\{9\}\{2\}$

Beachte Punkt vor Strich:

$\mathrm{2,5}-\mathrm{0,5}\cdot 32\{,\}5-0\{,\}5\cdot 3$

$=\mathrm{2,5}-\mathrm{1,5}=2\{,\}5-1\{,\}5$

$=1=1$