Here is a great example of an easy tune with a few non-diatonic chords thrown in for good measure.  Key of B Major.

CHORUS

1  5      4      1  5      4

1  5      4      1  3      4..

VERSE

1  5       4       1  5       4

1  5       4       1  5       4   1/3

2- 1/3  4  5

CHORUS

1  5      4      1  5      4

1  5      4      1  3      4..

RIDE

1  5       4       1  5       4

VERSE

1  5       4       1  5       4

1  5       4       1  5       4   1/3

2- 1/3  4  5

CHORUS

1  5      4      1  5      4

1  5      4      1  3      4..

BRIDGE

2- 5     6-    2- 5     6-

2- 5     6-    2- 5     6-..

CHORUS

1  5      4      1  5      4

1  5      4      1  3      4..

RIDE (OUTTRO)

1  5       4       1  5       4

As always, each number is a measure (4 beats), unless two chords are underlined meaning they share a measure (in that case each chord gets 2 beats).  All chords are assumed major unless they have a dash which indicates minor.

In the 8th bar of the verse there is a bar of 4  1/3 in which the 4 gets three beats and the 1/3 gets one beat.  In this case, three dots would be placed above the 4 and one dot would be placed about the 1/3.  Unfortunately, I couldn’t mark it properly using this editor.

Bruno Mars sings really high.  If you are wanting to sing this song… you may want to lower it to the key of A Major.  Or even G Major.  The beautiful thing about numbers is, YOU DON’T HAVE TO CHANGE A THING ON THIS CHART TO PLAY IN A DIFFERENT KEY!!

Pop quiz: What is the “non-diatonic” or (out of key) chord in this song??  Answer: The 3 Major chord that happens during each chorus in the second half of the seventh measure.  A 3 chord is supposed to be minor!  The 3 Major provides a neat harmonic moment during each chorus.

FOLLOW THE CHART AND PLAY ALONG!