[tex](1\frac{2}{3}+0,5)*(5\frac{2}{5}-3,9)=(\frac{5}{3}+\frac{1}{2})*(\frac{27}{5}-\frac{39}{10})=\frac{13}{6}*\frac{3}{2}=\frac{13}{2}*\frac{1}{2}=\frac{13}{4}=3\frac{1}{4}[/tex]
