Math & Logic · Ages 7–9
Riddle #72
You have $5 and your little brother has $1. You are feeling generous, so you give him $2. Now who has more money — you or your brother?
You solved this one before
Answer: Neither — you each have exactly $3
Handing over $2 doesn't only make him $2 richer, it makes you $2 poorer at the same moment — so the $4 gap between you closes twice as fast as you'd think. $5 − $2 = $3, and $1 + $2 = $3.