Something whole can be divided into equal pieces. In music, we mostly divide into 4 or 3 equal pieces. These pieces are of equal time, or duration. Whenever we divide the time, we use a new note type that looks different to show us that time change.
Equal pieces of 4 or 3 make up a whole.
|/ / / /||Four|
|/ / /||Three|
Let's focus on the whole that's divided into 4: / / / /
Four equal divisions each get an equal amount of time from the whole time that we're given. If we use only one of these divisions, there are three left. If we use two, there are two left. If we use three, there is one left. If we use them all, the whole time is used playing a whole note, or resting a whole rest.
The name of the one division we use is a quarter (one fourth). This is like using a quarter out of a dollar. We still have three quarters left to use. One division of four is a quarter note or quarter rest. We're either playing or resting for one quarter of the whole time we're given (1/4).
The name of two of the divisions we use is a half. This is because we still have another half of the whole left. We could call the half 'two quarters', but we want only one note (called a half note) to show that we use half the time playing or resting, out of the whole (any note has a rest counterpart with the same value).
As a fraction, two out of four is 2/4. To simplify, each number in our fraction can be divided by 2, bringing us to 1/2, like:
Two out of four is 2/4.
Divide each by 2:
2 on top, divided by 2 is 1.
4 on bottom, divided by 2 is 2.
Now 2/4 is 1/2.
We've used 2 and have 2 left: // // This is two sets of two, or two halves. Also, two halves make a whole, because two halves is two divided by two (2/2), which is one, or a whole.
|////||whole (in 4)|
We count three quarters with a dotted half note (we haven't read about that yet). So, we can use either three quarter notes, or one half note plus a quarter, to equal three quarters (// and /); or 3/4.
For a whole that's divided into 3 equal pieces, we use the same notes:
|///||whole (in 3)||//||half (two thirds of the whole, but still called a half note)|
|/||quarter (one third of the whole, but still called a quarter note)|
It's confusing that the name of the note in 3 doesn't match its time duration. But we must use the same looking note to see a time change. And just 3 quarter notes make up the whole duration: / / /.
Therefore, 3 quarters out of 3 beats is 3/3, three divided by three, which is one, or a whole.
Also, whenever we play one of these types of notes, we hold the tone of it until the time is complete.
So in 4, a whole holds four equal counts. A half holds for two counts. A quarter plays for one out of the 4 whole counts.
In 3, we hold a half note with a special dot that makes it 3 counts long. We use this dotted half note to show a single note to hold.
Finally, as a result of playing only part of the full (whole) count, some of the count is left over. During that leftover time period, we can add any notes or rests that fill that time amount. As long as we equal the whole time, such as 4 or 3, we can play any kind of divisions with half or quarter notes, or rests.
Recommended reading: The Dot
The next page frames our rhythm counting within measures and notes of sheet music.