9 + 10 = 21. PROOF

This equation is not true with decimal numbers. But what if we use other number bases? This viral math meme turns into a nice little puzzle, which, as they say, only geniuses can solve! Sources -10-21 #Modus_Indorum Subscribe: Playlist to watch all videos on MindYourDecisions: Send me your favorite puzzles/suggestions by email (address in video). I get so many emails that I may not reply, but I save all suggestions. This is the only channel to feature math topics suggested by people around the world. Support on Patreon to inspire mathematical discovery and make the world a better place: If you buy from the links below I may receive a commission for sales. This has no effect on the pri