what is a imposible to solve fraction problem

Question

I want a really hard problem that a fifth grader could answer if really good at math. I want it to be using unlike denominator fractions.

Answer 1

Example: 8⅘-5⅞.

A possible solution:

8-5+(⅘-⅞)=3+(32-35)/40=3+(-3/40)=3-3/40=(120-3)/40=117/40.

117/40=2³⁷/₄₀.