Arithmos: Math for nerds

Arithmos is mental math you can measure. Run timed drills, climb a rating against real players, and learn the shortcuts behind aptitude word problems.

DRILLS

Quick drill: pick addition, subtraction, multiplication or division, set the number ranges yourself and run for 30, 60 or 90 seconds. Your best score is kept for every setup.

Levels: 192 levels in six paths (addition, subtraction, multiplication, division, add and subtract, multiply and divide). Each level has its own ranges and clock, and the next one unlocks when you finish it.

ELO DUELS

Every scored drill and level run is rated. Your score is matched against another player's run at a similar rating, and you win or lose ELO points. The opponent does not have to be online: results wait for you in a "while you were away" list, with a rematch button.

Five tiers, each named for a mathematician: Scholar Euclid, Mathematician Fibonacci, Professor Gauss, Genius Euler and Legend Ramanujan. The standings show where you rank, and each drill setup has its own leaderboard.

APTITUDE AND REASONING

Word problems: speed and distance, profit and loss, percentages, interest, ratio and averages, time and work, or all of them mixed. Questions are generated, so you do not run out.

Reasoning: number and letter series, symbol puzzles, figure patterns and letter codes. Each puzzle is checked to have exactly one answer.

Practice mode is untimed and shows a worked solution for every question. Timed mode runs against the clock and keeps your best.

Games: largest number, prime hunt and sliding tiles.

LEARN

21 aptitude tricks, such as converting km/h to m/s, successive discounts, compound interest and pipes and cisterns. Each trick comes in a simple version and a deeper version, then a short set of practice questions. In aptitude, "learn the tricks" opens the lessons for the topic you are on.

PLAY WITH FRIENDS

Host a room and share the 4-character code or an invite link. Up to 5 players race on the same questions. Friendly races do not change your rating. Save players to a friends list or invite your recent rivals.

STREAK AND PET

Finish a drill each day to keep your streak going. Your pet kitten hatches and grows as you practise.

SIMPLE BY DESIGN

A plain, text-first look with a light and a dark theme, sound cues you can switch off, and a layout that fits tablets. Quick drill, learn and some aptitude topics work without an account. Levels, leaderboards, ELO duels and friends need a Google sign-in. You can delete your account in settings, or on the web at https://ovaanimations.in/arithmos_lite_delete_account.

The app shows ads. An optional monthly subscription removes them. In the EEA, UK and Switzerland you choose whether to allow personalised ads.

Made by Ova Animations.

Recent changes:
new look: a fresh paper-and-ink design, with a new icon
backup: sign in to save your progress and get it back on a new phone
online: quitting before half time or playing levels doesn't change your ELO; rematch challenges last 24 hours
puzzles: pause and resume