$\frac{1}{2}\cdot 4\frac{1}{5}=\frac{1}{2}\cdot \frac{21}{5}=\frac{21}{10}=2\frac{1}{10}$

$1\frac{1}{5}\cdot 4\frac{1}{5}=\frac{6}{5}\cdot \frac{21}{5}=\frac{126}{25}=5\frac{1}{25}$ $1\frac{1}{5}\cdot 4\frac{1}{5}=\frac{6}{5}\cdot \frac{21}{5}=\frac{126}{25}=5\frac{1}{25}$

$4\frac{1}{5}+2\frac{1}{2}\cdot 4\frac{1}{5}=4\frac{1}{5}+\frac{5}{2}\cdot \frac{21}{5}=4\frac{1}{5}+\frac{1}{2}\cdot \frac{21}{1}=4\frac{1}{5}+\frac{21}{2}=4\frac{1}{5}+10\frac{1}{2}=4\frac{2}{10}+10\frac{5}{10}=14\frac{7}{10}$

 

$\frac{1}{2}\cdot 7\frac{2}{5}=\frac{1}{2}\cdot \frac{37}{5}=\frac{37}{10}=3\frac{7}{10}$

$1\frac{1}{5}\cdot 7\frac{2}{5}=\frac{6}{5}\cdot \frac{37}{5}=\frac{222}{25}=8\frac{22}{25}$

$7\frac{2}{5}+2\frac{1}{2}\cdot 7\frac{2}{5}=7\frac{2}{5}+\frac{5}{2}\cdot \frac{37}{5}=7\frac{2}{5}+\frac{37}{2}=7\frac{2}{5}+18\frac{1}{2}=7\frac{4}{10}+18\frac{5}{10}=25\frac{9}{10}$