Singers need to Transpose (Life on Mars)

Singers have to use transposing for many songs.

Example:

A male singer knows the highest note he can reach is an F. He's given Life on Mars by David Bowie. He can see that the highest note in the sheet music is a b Flat.

So, to find out how many semitones (smallest interval in western music, equal to a twelfth of an octave) this note needs to fall to come down to an F, he looks at a piano.

So he could see that the notes needed to come down 5 semitones in order to sing this song.

Now he went to the start of the song and knows that the first note he sings has to start 5 semitones down.

So instead of singing the song F G A:

He will start the song semitones lower. 
F G and A transposed 5 semitones (either use the transposition chart (downwards)) OR work it out on a piano.

F becomes:

F becomes a C.

G becomes:

G becomes a D.

And finally, A becomes: