Math Riddles

Hard riddles are multi-step problems. You can't solve them in one equation — there are intermediate steps, and getting the approach wrong means starting over. Work rate problems (Alice paints a room in 6 hours, Bob in 4, how long together?) are a staple here.

The snail-on-a-wall type problems also live at this level. They look like simple rate problems but have an off-by-one trap built in — the final step behaves differently from all the others. If your answer is suspiciously round, double-check the end condition.

Number theory shows up too: digit manipulation, divisibility, modular arithmetic. These are more about clever thinking than heavy computation. If you find yourself doing long division, there's probably a simpler approach you haven't spotted yet.