Here’s a helpful tip for Pi Day: On a Windows computer, you can enter the symbol for Ï€ by holding down the ALT key, typing 227 using the numeric keypad,^{1}The number keys at the top of the keyboard do not work for this. If you have a laptop computer, you’ll need to enable the embedded numeric keypad before trying this. and then releasing the ALT key.

The mildly geeky amongst us will remember this by noting 22/7 is a common approximation for pi. The geekier will avoid using this approximation and instead remember enough significant digits^{2}I find 3.1415926 is adequate significant digits for all my purposes. Or better yet, just use the “pi” button on the calculator. of pi.