How it works

Memory Challenges is built on a simple idea: some things are worth knowing cold. Math facts should be automatic — not counted out on fingers, just known. Here's the loop:

• Practice a few minutes a day. Smart flashcards bring each fact back right before you'd forget it, so it settles into long-term memory.

• Take the 3-minute Challenge. Type as many answers as you can. Each card appears once, there are no second chances, and the clock doesn't stop.

• Watch the mastery map. Every card has a square. Answer a fact in under 3 seconds in two different challenges and its square turns green — that fact is automatic.

• Miss a fact in a challenge and it goes straight back into practice, so you're always working on exactly what you don't know yet.

• Turn the whole map green and the deck earns its gold star. That's mastery: every single fact, automatic.