If you look at the first note in each measure, you will know how many beats are in a measure. Then, look at how many beats are in your note. For example, since a 4/4 time signature has four beats, a whole note will take up a full measure. In 3/4 time, a dotted half note with three beats will fill the measure. In 2/4 time, a half note (which has two beats) will complete a measure.