In the next set of lessons, you will see a perfect fifth lit up on your instrument and you will write it in music notation.
For example, if the bottom note is sharp, the top note will be sharp too.
Or, if the bottom note is flat, the top note will be flat too.
As we learned earlier, a fifth built on this note will come out flat.
Therefore, if the bottom note is B, the top note F would require a sharp. Or if Bb, is used, then F would be natural.