11 × 13 = ?
Mental math. No course, no fluff — just practice.
11x13 is a pure practice app: open it and go. Short problems, several answers, one correct. Ten minutes a day make numbers feel natural again.
Free to download — the basic operations stay free forever.
Four packs
Basic operations
Free foreverThe foundation: add, subtract, multiply, divide — from times tables to 11×13 and beyond.
Advanced
Percentages, fractions, roots, powers — the math of everyday life, school and work.
Higher
Derivatives and integrals in your head — routine for high school and university.
Geometry
Symbol equations, counting corners, matching shapes — geometry made tangible, entirely without words.
How it works
25% · 80 = ?
Wordless problems
No word problems, no explanations — just the math. That's why 11x13 works equally well in every language.
↗12·B3
Levels & bands
Your level grows with every correct answer. New bands introduce genuinely new kinds of problems — it stays challenging, never repetitive.
★ Score
Visible progress
Streak, week-over-week comparison, a level per operation and history curves show what you've mastered. A Home Screen widget brings the problem of the day, a reminder at your chosen time keeps you going. The notebook keeps your last 100 mistakes on this device. Review them in short, untimed rounds.
∞
Everything — buy permanently or subscribe
Use every package permanently with a one-time purchase or for the duration of a subscription. The 14-day app trial ends automatically without starting a subscription. Basic operations remain free.
Purchase and subscription prices on the App Store