SUMFLASH

Numbers flash by. Add them in your head.

Numbers appear one at a time, each for just a moment. Enter the total. This is flash mental math, the way it's practiced with the soroban (Japanese abacus).

Download on the App Store

See why you missed

After each answer, review every number that flashed along with the running total at that point. Numbers where a carry happened are highlighted, so you can spot exactly where you slipped. Replay the same problem, or replay it slowly.

How it works

Tap StartNumbers appear one at a time.
Enter the totalType your answer on the keypad.
Result and reviewSee the numbers and running totals to find where you slipped.

Screens

Review screen listing 15 numbers with running totals; numbers with a carry are blue

Home screen (Chalkboard theme) with a 4-day streak and level 10

Features

Choose from 30 levels (1 digit × 3 numbers × 1 s up to 3 digits × 15 numbers × 0.5 s)
Set the speed yourself, anywhere from 0.2 to 5.0 seconds
Your streak on the home screen. Miss one day a week and your streak stays alive
A daily reminder at the time you choose (quiet on days you've practiced)
Numbers simply appear and disappear, with no animation getting in the way
Five themes (Minimal / Washi / Neon / Chalkboard / Sakura)
Separate profiles for each family member
Ranked play (1 digit × 10) with Game Center leaderboards
Pick addition, subtraction (mixed plus and minus), multiplication, or division from the home screen tabs. Each has its own 30 levels
Numbers read aloud
Records stay on your device (if you're signed in to Game Center, only your best ranked-play time is sent to Apple for the leaderboard). No account needed

Premium

No ads. Monthly auto-renewable subscription. Cancel anytime in iPhone Settings › Apple ID › Subscriptions. Premium only removes ads. Every other feature is free.

About ads

Ads appear at the bottom of the home screen and between sets. No ads while numbers are flashing, while you're entering your answer, or while you're reviewing. Premium has no ads.