The notes in different octaves are so closely related that when musicians talk about a note, a "G" for example, it often doesn't matter which G they are talking about. We can talk about the "F sharp" in a G major scale without mentioning which octave the scale or the F sharp are in, because the scale is the same in every octave. Because of this, many discussions of music theory don't bother naming octaves. Informally, musicians often speak of "the B on the staff" or the "A above the staff", if it's clear which staff they're talking about.
But there are also two formal systems for naming the notes in a particular octave. Many musicians use Helmholtz notation. Others prefer scientific pitch notation, which simply labels the octaves with numbers, starting with C1 for the lowest C on a full-sized keyboard. The following Figure 4.3 shows the names of the octaves most commonly used in music.
The octave below contra can be labelled CCC or Co; higher octaves can be labelled with higher numbers or more lines. Octaves are named from one C to the next higher C. For example, all the notes between "great C" and "small C" are "great". One-line c is also often called "middle C". No other notes are called "middle", only the C.
Give the correct octave name for each note.