About PiNumpad. The Natural Logarithm Of 2

PiNumpad is a free memory trainer for the natural logarithm of 2 (0.69314718055994...), the natural logarithm of 2, the area under the curve 1/x from 1 to 2. This page is the practice mode: the numpad path is hidden and you tap the natural logarithm of 2 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.

ln 2 governs the doubling time of exponentially growing systems, appears in information theory as the conversion between nats and bits, and is the alternating harmonic series sum. 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 programmers, information theorists, finance students, and anyone who works with logarithms, algorithm complexity, or exponential models. It runs entirely in the browser with no account, no installation, and no cost. Progress is saved locally using your browser's storage.

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