\[8\frac{5^{\backslash 4}}{9} + 7\frac{3^{\backslash 9}}{4} + 12\frac{7^{\backslash 3}}{12} =\]
\[= 27\frac{20 + 27 + 21}{36} = 27\frac{68}{36} =\]
\[= 28\frac{32}{36} = 28\frac{8}{9}\]