Fun fact: the classic version of this riddle casts you as a train conductor trying to count the number of train cars in a train, where all you can do is walk from one car to the next and turn the light on or off! Here is the puzzle as described by the riddle section of FiveThirtyEight. If you want to dig deeper into the math, Professor Tim Black has a nice blog about this puzzle analyzing the efficiency of different solutions and Ben Tupper has a video walking through several possible approaches.

Puzzles like this one challenge your brain to figure out something new, with no clear ties to problems you already know how to solve! The more of these you tackle, the more equipped you become at adapting to new challenges that come your way. Think back to how impossible this problem seemed at first, and reflect on the “aha” feeling you may have experienced once you realized returning to the starting candle would help. The TED-Ed riddle series is a great place to find more puzzles, each different from the last!