\[8\frac{1^{\backslash 5}}{8} - 4\frac{7^{\backslash 4}}{10} = 8\frac{5}{40} - 4\frac{28}{40} =\]
\[= 7\frac{45}{40} - 4\frac{28}{40} = 3\frac{45 - 28}{40} = 3\frac{17}{40}\]