About PiNumpad. The Square Root Of 2

PiNumpad is a free memory trainer for the square root of 2 (1.41421356237309...), the square root of 2, the first known irrational number. This page shows all the numpad paths for the square root of 2, use it to learn the visual patterns before testing yourself in Play mode.

Learn the numpad paths. Study mode shows all numpad paths for the constant at once, laid out group by group. Each group is displayed as a path diagram on the 3×3 numpad grid. You can tap any group's path card to hear the corresponding melody, the audio encoding that accompanies the visual pattern.

The irrationality of √2 was proved by the ancient Greeks, legend has it that the discovery so disturbed the Pythagoreans that they drowned the mathematician who found it. It appears in geometry, signal processing, and the diagonal of any unit square. Scroll through the groups to build a mental map of the full sequence. Tap a path card to play its melody. Use this mode before Learn or Play to orient yourself with the patterns.

PiNumpad is designed for geometry students, engineers, computer scientists, and anyone interested in the history of mathematics and irrational numbers. 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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