$(\frac{2}{7}{)}^2=\frac{2}{7}\ast \frac{2}{7}=\frac{2\ast 2}{7\ast 7}=\frac{4}{49}$

$(\frac{2}{3}{)}^3=\frac{2}{3}\ast \frac{2}{3}\ast \frac{2}{3}=\frac{2\ast 2\ast 2}{3\ast 3\ast 3}=\frac{8}{27}$

$(\frac{1}{5}{)}^3=\frac{1}{5}\ast \frac{1}{5}\ast \frac{1}{5}=\frac{1\ast 1\ast 1}{5\ast 5\ast 5}=\frac{1}{125}$

$(3\frac{1}{3}{)}^2=(\frac{10}{3}{)}^2=\frac{10}{3}\ast \frac{10}{3}=\frac{10\ast 10}{3\ast 3}=\frac{100}{9}=11\frac{1}{9}$