$a)5\frac{1}{7}:0,9+0,1=\frac{36}{7}:\frac{9}{10}+0,1=$   $\frac{36}{7}\cdot \frac{10}{9}+0,1=$   $\frac{4}{7}\cdot \frac{10}{1}+\frac{1}{10}=$   $\frac{40}{7}+\frac{1}{10}=$   $\frac{400}{70}+\frac{7}{70}=\frac{407}{70}=5\frac{57}{70}$  

 

$b)\frac{1}{5}-0,01:0,2=\frac{2}{10}-0,1:2=0,2-0,05=0,15$ $b)\frac{1}{5}-0,01:0,2=\frac{2}{10}-0,1:2=0,2-0,05=0,15$  

 

$c)1,05\cdot \frac{2}{3}-0,46=$   $\frac{105}{100}\cdot \frac{2}{3}-0,46=$   $\frac{21}{20}\cdot \frac{2}{3}-0,46=$   $\frac{7}{20}\cdot \frac{2}{1}-0,46=$   $\frac{7}{10}-0,46=0,7-0,46=0,24$  

 

$d)\left(72-2\cdot 9\right):\frac{1}{2}=\left(72-18\right)\cdot 2=$   $54\cdot 2=108$  

 

$e)\left(2-7\right)\cdot \left(6:1\frac{1}{5}\right)=$   $\left(-5\right)\cdot \left(6:\frac{6}{5}\right)=$   $\left(-5\right)\cdot \left(6\cdot \frac{5}{6}\right)=\left(-5\right)\cdot 5=-25$  

 

$f){\left(\frac{3}{5}\right)}^2:{\left(\frac{2}{5}\right)}^2-{\left(1,5\right)}^2=$   $\frac{9}{25}:\frac{4}{25}-{\left(\frac{15}{10}\right)}^2=$   $\frac{9}{25}\cdot \frac{25}{4}-{\left(\frac{3}{2}\right)}^2=$   $\frac{9}{4}-\frac{9}{4}=0$  

 

$g){\left(-4\right)}^2-{\left(-3\right)}^2=\left(-4\right)\cdot \left(-4\right)-\left(-3\right)\cdot \left(-3\right)=16-9=7$