A typical piano has 88 keys spanning just over seven octaves. There are other, smaller keyboards or synthesizers that have fewer keys – most come in increments of 25, 32, 49, 61 or 72 keys.

An 88-key piano has seven octaves plus three lower notes (B, B flat and A) below the bottom C. It has 52 white keys and 36 black keys (sharps and flats), with each octave made up of seven white keys ...

Let’s go back to the days before the piano, when composers wrote for the harpsichord, which has just 60 keys, and each key is its own note, its own sound. Around 1700, a musical technician named ...