Music is written on a staff: five lines with four spaces between them. Each line and each space is a white key, and the higher a note sits on the staff, the higher it sounds. Going from a line to the space just above it is one letter up.
The treble clef at the start of the staff curls around the second line from the bottom, which makes that line G (the G above middle C, G4). That's why it's also called the G clef. Right-hand music is usually written in the treble clef.
From the bottom, the lines are E G B D F ("Every Good Boy Does Fine") and the spaces spell F A C E. Middle C sits on a short extra line of its own just below the staff, called a ledger line.
The treble clef from middle C up. Lines: E G B D F. Spaces: F A C E.
Practice
The lines
Play the note on the staff. These are all on the lines: E G B D F.
AC4SDDEFFGGHAJBKC5LD;E'FGABC6WETYUOP
Computer keys: ASD… for the white keys, WET… for the black keys, ZX move an octave.
More info
Tips
Learn a few landmark notes (middle C, the G line, and the top F) and read other notes as steps from the nearest one.
Playing the exercises
Use a MIDI keyboard (Chrome, Edge, Firefox or Opera), the computer keys (ASD… for white keys, WET… for black keys, ZX to move an octave), or tap the keys on the screen. A key lights up after a couple of wrong tries.
The answers
Which line does the treble clef curl around? The second line, G. The curl sits on the second line from the bottom and names it G, so it's also called the G clef.
What are the lines of the treble staff, from the bottom? E G B D F. Every Good Boy Does Fine: E G B D F. The spaces are F A C E.
In the treble clef, which note is in the top space? E. The spaces spell F A C E from the bottom, so the top space is E.
Where is middle C in the treble clef? On a ledger line below the staff. Middle C is below the treble staff, on a short line of its own.