About PiNumpad. Prime Numbers

PiNumpad is a free memory trainer for prime numbers (2, 3, 5, 7, 11, 13, 17, 19...). A prime is an integer greater than 1 divisible only by 1 and itself. This page is the practice mode: the numpad path is hidden and you tap prime numbers digits entirely from memory. Your score is saved locally between sessions.

Practice from memory. In play mode, the numpad path is hidden. You must tap each digit of the sequence from memory alone, with no visual guide. A correct tap advances the path; an incorrect tap triggers a brief error sound and a shake. Your score, the number of digits or primes you can enter without error, is stored locally so you can track progress across sessions.

Primes are the atoms of arithmetic. They underpin modern cryptography (RSA encryption, Diffie-Hellman key exchange), appear in physics and biology, and have fascinated mathematicians since antiquity. The sequence is infinite, and its distribution remains deeply mysterious. Tap the digits on the on-screen numpad in the correct sequence. Use Study mode first to learn the path, then switch to Play to test retention. Hold the hint button to reveal the path briefly if you are stuck.

PiNumpad is designed for cryptography students, competitive memorisers, maths olympiad participants, programmers, and anyone who wants to know the first hundred primes by heart. It runs entirely in the browser with no account, no installation, and no cost. Progress is saved locally using your browser's storage.

Study · Learn · Digits · How to memorise · About

About Privacy Policy Terms of Use How to memorise hello@pinumpad.com