Score0
Time30s
Streak0
Number Rush
A quick maths sprint for anyone who enjoys beating the clock.
Build notesUnder the hood, without the lecture
Number Rush is a short arithmetic sprint. The generator aims for questions that feel varied without suddenly handing someone unpleasant homework.
Questions with guardrails
Operands stay inside friendly ranges, and multiplication appears less often than addition. The answer is stored with the question, so checking never has to parse the displayed operator.
Restarts without ghost timers
A run ID gives every restart a fresh timer lifecycle. Cleanup removes the previous interval, preventing two countdowns from racing each other.
const multiply = Math.random() > 0.62;
return {
left, right,
sign: multiply ? "×" : "+",
answer: multiply ? left * right : left + right,
};