a) [tex]5\cdot\frac{5}{9}=\frac{5\cdot5}{9}=\frac{25}{9}=\boxed{2\frac{7}{9}}[/tex]
b) [tex]3\cdot\frac{3}{5}=\frac{3\cdot3}{5}=\frac{9}{5}=\boxed{1\frac{4}{5}}[/tex]
c) [tex]3\cdot\frac{5}{6}=\frac{3\cdot5}{6}=\frac{15}{6}=\boxed{2\frac{3\div2}{6\div2}=3\frac{1}{2}=3{,}5}[/tex]
d) [tex]12\cdot\frac{2}{5}=\frac{12\cdot2}{5}=\frac{24}{5}=\boxed{4\frac{4}{5}}[/tex]
e) [tex]\frac{9}{10}\cdot8=\frac{9\cdot8}{10}=\frac{72}{10}=\boxed{7\frac{2}{10}=7{,}2=7\frac{2\div2}{10\div2}=7\frac{1}{5}}[/tex]
f) [tex]\frac{3}{4}\cdot17=\frac{3\cdot17}{4}=\frac{51}{4}=\boxed{12\frac{3}{4}=12{,}75}[/tex]
