Math practice · reimagined
Units
Turn Units into a fight you actually want to win. Every problem is an attack — solve it faster than your opponent and you land the hit.
Ages 4–99+ · no download · plays in your browser · 23 languages
How it works
Units
Pick a fighter, choose Units, and trust your numbers. The faster and cleaner you solve, the harder you hit — from gentle early grades all the way to Olympic-level challenges.
Trading between metric units — and the metric system loves the number 1000.
1 km = 1000 m and 1 kg = 1000 g. To go from the big unit to the small one, multiply by 1000 (3 kg = 3000 g); to go back up, divide by 1000. Just slide the digits and keep track of the unit you're asked for.
— Quick answers —
Units: the short FAQ
- Is Units free to play?
- Yes. Units is free to play right in your browser — the whole curriculum, no download, no signup. Paid plans later unlock the full fighter roster, every stage and saved progress.
- Who is Units for?
- Anyone from 4 to 99+. The early grades stay gentle for beginners, while the higher tiers will make even the confident sweat.
- Do I need to download anything to play Units?
- Nope. Units runs in any browser, on a laptop, tablet or phone.
- Can Units be used in the classroom?
- Absolutely. Teachers run Units with a whole class and track who's improving — see the schools plan for per-student pricing and a teacher dashboard.