\[4\frac{2^{\backslash 9}}{7} - 1\frac{4^{\backslash 7}}{9} = 4\frac{18}{63} - 1\frac{28}{63} =\]
\[= 3\frac{81}{63} - 1\frac{28}{63} = 2\frac{53}{63}\]