\[\left( 1\frac{1}{3}p^{12}q^{6} \right)^{2} = \left( \frac{4}{3}p^{12}q^{6} \right)^{2} =\]
\[= \frac{16}{9}p^{24}q^{12} = 1\frac{7}{9}p^{24}q^{12}\]