Continuing on the subject of using scales and numbers to represent notes on the ukulele…
The Roman numeral or number system as I explained in “Spelling Ukulele Chords” and “Constructing Ukulele Scales” can be used to take notes from one key and figure out the same chord or scale in another key. You can use the number system to rework a song and change it to a different key so that it fits on the ukulele better. This is called transposing. With it, you can transform any melody or chords into another key. Awesome, this can really make things easier.
Transposing Melody
Let’s use “Twinkle, Twinkle” for an example and start with transposing a melody. In C, the first seven notes are: C C G G A A G. But say you want to play it in G (just agree, “yes I want to play it in G…”). You would take the C major scale that the song is played in and write it out:
C D E F G A B C
(Go learn how scales are made if you are curious.) Then, locate the notes that you used in the melody.
(C) D E F (G) (A) B (C)
Attach the appropriate numbers to the notes.
1 5 6 C D E F G A B C
Then add the G scale below the C scale.
1 5 6 C D E F G A B C G A B C D E F# G
Now use the 1 5 6 notes from the G scale to play the melody. This becomes: G G D D E E D. You can use the numbers that represent the notes to change any melody to a different key. If you are going to transpose the entire melody, you might want to just make a chart like this:
1 2 3 4 5 6 7 8 C D E F G A B C G A B C D E F# G
Then you don’t have to figure out which notes have what numbers. You can just look and see, “okay F would be C, B would be F#, etc…”
Transposing Chords
Transposing chords uses the same idea. The only difference is that the chords have definitions attached to them (major, minor, 7th, etc.). One of the easiest ways to learn this is to transpose a Hawaiian song. Most Hawaiian music is based around three chords 1, 4, and 5. Take the fist part of “Hi’ilawe“:
C F C Kumaka ka 'ikena ia Hi'ilawe G7 C Ka papa lohi mai a'o Maukele (2x)
1 4 5 C D E F G A B C
If you wanted to transpose it into G, you would add the G scale and substitute the G chords for the C chords.
1 4 5 C D E F G A B C G A B C D E F# G
G C G Kumaka ka 'ikena ia Hi'ilawe D7 G Ka papa lohi mai a'o Maukele (2x)
Many times you have to figure this out in your head while the song is going on. A mainstream song will probably have more chords, so you just add those numbers to your scale.