Sumday: Mental Math Practice

Five minutes a day to get your mental math back. Sumday is a quiet daily routine for adults: real arithmetic, not puzzles, that keeps your number sense sharp. The more we rely on calculators and spreadsheets, the slower the math in our head gets. Sumday wakes it up with one short set a day that mixes addition, subtraction, multiplication, division, percentages and estimation. Learn one practical math trick a day, the kind school never taught you, and feel your speed come back. WHO IT'S FOR • Adults who feel their mental math isn't what it used to be • Anyone preparing for aptitude or job tests with timed number questions • People who want to split a bill, work out a discount or estimate a total in seconds • Anyone looking for light daily brain training HOW IT WORKS 1. Solve today's set of 20 questions. Five minutes is enough. 2. Check your results: accuracy and response time, compared with yesterday. 3. Unlock today's technique card and use it in tomorrow's set. 4. Come back tomorrow. A daily reminder keeps your streak going. FEATURES • Today's set: 20 mixed arithmetic questions across 7 types: addition, subtraction, multiplication, division, percentages, estimation and everyday math • Adaptive difficulty: questions get harder as you improve and ease off when you get stuck (12 levels) • Daily technique cards: 30 mental math tricks, from rounding shortcuts to quick percentages • Results report: accuracy, average response time and change since yesterday on one screen • Progress charts: daily and weekly trends in accuracy and speed • Streaks and a gentle daily reminder NO ACCOUNT, NO SERVER No sign-up needed. Your records stay on your device, and it works in airplane mode. PREMIUM (OPTIONAL) A one-time purchase removes ads and unlocks 3 practice modes (estimation, percentages, everyday math), Challenge mode (endless survival with 3 lives), detailed statistics and all 30 technique cards. No subscription. Available in English, Korean and Japanese. Start your five minutes of math practice today.