Numvolt: Mental Math Trainer

Numvolt is the joy of getting better at mental math. Open, calculate, understand, repeat. No account, no ads, optional one-time purchase. TEN TOPICS, A HUNDRED RUNGS EACH Addition, subtraction, multiplication, division, fractions, percentages, order of operations, powers, algebra and square roots. Each topic has its own 100-rung journey; the difficulty adjusts during the session, block by block. You pick your starting point at setup, and you can always replay a lower level. EVERY MISTAKE EXPLAINED A wrong answer takes nothing away. The correction shows the method — "take away 20, then add 1" — not just the result. In Zen mode there is no timer: time to understand. SPRINTS AND A DAILY CHALLENGE 15, 30 or 60 seconds on the + − × ÷ mix. +1 per correct answer, −1 per mistake. The daily challenge is the same 60-second series for everyone, all day long. A LADDER FROM YOUR CITY TO THE WORLD Join the ladder with a nickname and your city. Your best sprint is ranked on six rungs: city, county, region, country, continent, world. After every sprint you see exactly what you climbed — "5th → 2nd · Rhône" — and how many points you need to overtake the next player. Only your nickname, city and scores are published. Never your exact location. DUEL ON ONE PHONE Two players, the same questions in the same order, 30 seconds each. Scores are revealed at the end. YOUR PROGRESS, VISIBLE XP, overall level, accuracy, day streak, seven-day chart, level per topic and session history. A Home Screen widget shows your daily goal and starts a sprint in one tap. WHAT STAYS WITH YOU Your progress lives on your iPhone, in the app's storage. No account. Anonymous usage counters, which you can switch off in Settings, only tell us where the app gets stuck. Fractions and decimals accepted on the keypad. Light, dark or automatic appearance. English and French.