About this app
Learning basic probability is quick & easy, and will pay off for the rest of your life. You'll get better grades in school, do better at job interviews, and make better decisions. We'll start with the easiest quizzes imaginable, and work our way to challenging problems one tiny step at a time. Your friends & family will be impressed you can do this! * No advertisements * No sign-up screens * Supports dark theme * Supports portrait & landscape mode * Optional narrator voice-over * Option to answer with your voice * Calculations are verified with simulations When using audio mode with earphones or speakers, the app reacts to taps anywhere on the screen, so you can practice without looking at the screen.
Latest release
What’s New
You can now run custom simulations
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Aug 6, 2026 · 3:32 PM Free
Screenshots
