Musical notation uses written symbols to represent music. It includes staff lines to notate pitches, bar lines to divide music into measures, and ledger lines to notate pitches outside the staff. The staff contains five lines that are numbered from bottom to top. Bar lines come in three types: single, double, and end bars. Single bars divide music into measures while double bars separate sections and end bars indicate the end of a piece. Repeat signs use two dots to signify repeating a section.