Brain Teasers

These are problems that trip up people who are good at math. Infinite series that converge to unexpected values. Game theory scenarios where the "rational" strategy seems irrational. Paradoxes where both sides of an argument look correct until you find the hidden assumption.

Read the proof even if you got the answer right. Einstein-level problems often have multiple valid approaches, and the proof might show a cleaner one than whatever you cobbled together. If you're consistently solving these, you're in rare company.