The piano keyboard consists of both white keys and black keys arranged in a particular pattern…
Notice that the black keys come in groups of twos and threes, a pattern that repeats itself all the way up and down the keyboard…

Also notice that this pattern repeats itself every twelve notes…

And, within each group of twelve notes, there are always seven white keys and five black keys…

By the way, if you ever wondered how important the black keys are, imagine trying to play a keyboard that looks like this…

By the way, Frank has had stress nightmares about this very thing!