do we always need improper fraction to subtract?
example
$$\\6\frac{3}{8}-2\frac{2}{8}\\\\ =6+\frac{3}{8}-2-\frac{2}{8}\\\\ =6-2+\frac{3}{8}-\frac{2}{8}\\\\ =4+\frac{1}{8}\\\\ =4\frac{1}{8}$$
NO Definitely not!