The 7 Notes
The piano looks like it has a bajillion notes, but it's really just seven
The piano looks like it has a bajillion notes, but it's really just seven notes: A, B, C, D, E, F, G. And then they just repeat. A, B, C, D, E, F, G going up the entire keyboard. That's it.
Think of it like days of the week. After Sunday, you start back at Monday. Same idea.