Seven names repeat
Start at middle C: C, D, E, F, G, A, B, C
Begin on middle C and read the highlighted white keys from left to right: C, D, E, F, G, A, B, C. After G, the musical alphabet starts again at A. Moving right gives a higher pitch; moving left gives a lower pitch.
Find C just left of two black keys. A small number in a label such as C4 distinguishes higher and lower copies of a letter; C4 is middle C. For now, read just the letters.
What is the name of this highlighted white key?
A keyboard landmark
Meet middle C
Position on a full piano
Middle C is a useful shared landmark for reading music. On a full 88-key piano it lies near the centre, not at the exact midpoint.
The close view shows C beside two black keys. The overview shows where that C sits on the full piano.
Read these highlighted white keys from left to right. Which sequence is correct?
Recap
Same letter, different height
Position on a full piano
These keys are both C, but the next C to the right sounds higher. This distance is an octave. C4 means middle C; C5 means the next C above it.
Octave numbers are useful addresses, not extra note names or staff-line numbers. You do not need to memorise them for these note-naming tasks.