a)

$\frac{1}{2}+1,5=0,5+1,5=2$  

$3,2-1\frac{1}{3}=3\frac{2}{10}-1\frac{1}{3}=3\frac{1}{5}-1\frac{1}{3}=3\frac{3}{15}-1\frac{5}{15}=\left(3\frac{3}{15}+\frac{10}{15}\right)-\left(1\frac{5}{15}+\frac{10}{15}\right)=3\frac{13}{15}-2=1\frac{13}{15}$  

$7,3-4\frac{2}{25}=7,3-4\frac{2\cdot 4}{25\cdot 4}=7,3-4\frac{8}{100}=7,3-4,08=3,22$  

b)

$2,4\cdot \frac{3}{8}=2\frac{4}{10}\cdot \frac{3}{8}=2\frac{2}{5}\cdot \frac{3}{8}=\frac{\sout{12}{}^3}{5}\cdot \frac{3}{\sout{8}{}_2}=\frac{9}{10}=0,9$  

$2\frac{3}{4}:2,75=2\frac{3}{4}:2\frac{75}{100}=2\frac{3}{4}:2\frac{3}{4}=1$  

$2,5\cdot 2\frac{1}{2}=2\frac{1}{2}\cdot 2\frac{1}{2}=\frac{5}{2}\cdot \frac{5}{2}=\frac{25}{4}=6\frac{1}{4}=6,25$        

c)

${\left(0,2+\frac{1}{2}\right)}^2={\left(0,2+0,5\right)}^2={0,7}^2=0,49$  

${\left(1\frac{3}{4}-0,85\right)}^2={\left(1,75-0,85\right)}^2={0,9}^2=0,81$  

${\left(6\frac{1}{5}-5,94\right)}^2={\left(6,2-5,94\right)}^2={\left(\left(6,2+0,06\right)-\left(5,94+0,06\right)\right)}^2={\left(6,26-6\right)}^2={0,26}^2=0,0676$  

d)

${\left(0,5\right)}^3+{\left(\frac{1}{3}\right)}^2={\left(\frac{1}{2}\right)}^3+\frac{1}{9}=\frac{1}{8}+\frac{1}{9}=\frac{9}{72}+\frac{8}{72}=\frac{17}{72}$  

${\left(0,1\right)}^3+{\left(\frac{1}{5}\right)}^2=0,001+{\left(0,2\right)}^2=0,001+0,04=0,041$  

${1,4}^2+{\left(\frac{4}{5}\right)}^2=1,96+{0,8}^2=1,96+0,64=2,6$