$\frac{2}{3} - \frac{1}{3} = \frac{1}{3}$;
$3\frac{1}{6} - \frac{1}{3} = 3\frac{1}{6} - \frac{2}{6} = 2\frac{5}{6}$;
$1 - \frac{1}{3} = \frac{2}{3}$;
$-\frac{1}{3} - \frac{1}{3} = -\frac{2}{3}$;
$\frac{4}{9} - \frac{1}{3} = \frac{4}{9} - \frac{3}{9} = \frac{1}{9}$;
$2 - \frac{1}{3} = 1\frac{2}{3}$;
$-\frac{1}{9} - \frac{1}{3} = -\frac{1}{9} - \frac{3}{9} = -\frac{4}{9}$;
$\frac{5}{9} - \frac{1}{3} = \frac{5}{9} - \frac{3}{9} = \frac{2}{9}$.

$\frac{1}{2} * \frac{2}{5} = \frac{2}{10} = \frac{1}{5}$;
$2\frac{1}{2} * \frac{2}{5} = \frac{5}{2} * \frac{2}{5} = 1$;
$5 * \frac{2}{5} = 2$;
$\frac{5}{14} * \frac{2}{5} = \frac{2}{14} = \frac{1}{7}$;
$1 * \frac{2}{5} = \frac{2}{5}$;
$\frac{1}{4} * \frac{2}{5} = \frac{1}{10}$;
$0 * \frac{2}{5} = 0$;
$10 * \frac{2}{5} = 4$.