Live 1v1

Duel a friend at mental math, right now.

Ten questions. Five numbers flashed one at a time, no abacus and no paper. Send one link and you both play the exact same questions at the exact same moment.

See how it works

🔟 10 questions🎁 No signup⏱️ About 2 minutes

How it works

Three steps, no account

Nothing to install and nothing to sign up for — the whole duel runs in the browser, on both phones.

1
Type a name and pick a style
Type the name your friend will see, choose the abacus rule the questions are built on, and how fast the numbers flash.
2
Send the link
You get a short link that lives for 30 minutes and works once. Your friend opens it, picks a name, and you are paired.
3
Play the same ten questions
Both screens flash identical questions together. Answers stay hidden until you have both locked in, then the round is revealed.

Question styles

Pick the rule the questions are built on

Every question is engineered around a specific soroban technique, the same way the rule worksheets are — so a duel drills something, not just anything.

Direct moves

Straight adds and subtracts with no complement — the fastest, most forgiving duel.

Small friends

Every question leans on a 5-complement, adding and subtracting alike.

Big friends

Every question leans on a 10-complement — carrying and borrowing across rods.

Combined

The moves that need both complements at once, the hardest single rule on the ladder.

Mixed

All eight rules shuffled together — the closest thing to a real competition round.

Fair by design

Same questions, same second

Questions come from the server, not from either phone, and neither side sees a reveal until both have locked in or the answer window runs out. Accuracy decides the duel; if you tie on score, the faster total thinking time wins.