Lyrics:

Three is a magic number
Yes it is, it's a magic number
Somewhere in ancient mystic trinity
You get three as a magic number

The past and the present and the future
Faith and Hope and Charity
The heart and the brain and the body
Give you three as a magic number

It takes three legs to make a tripod
Or to make a table stand
It takes three wheels to make a vehicle
Called a tricycle

Every triangle has three corners
Every triangle has three sides
No more, no less
You don't have to guess
When it's three, you can see
It's a magic number

A man and a woman had a little baby
Yes, they did
They had three in the family
And that's a magic number

3-6-9, 12-15-18, 21-24-27, 30
3-6-9, 12-15-18, 21-24-27, 30

Now the multiples of 3
Come up three times in each set of ten
In the first you get 3, 6, 9
And in the 'teens' ten it's 12, 15, and 18
And in the 'twenties' you get 21, 24, 27
And it comes even on 30, yeah

Now multiply backwards from 3 x 10:
3 x 10 is 30, 3 x 9 is 27, 3 x 8 is 24, 3 x 7 is 21
3 x 6 is 18, 3 x 5 is 15, 3 x 4 is 12
And 3 x 3 is 9, and 3 x 2 is 6
And 3 x 1 is 3 of course

Now dig the pattern once more:
(3) 3-6-9
(12) 12-15-18
(21) 21-24-27... 30

Yeah, 30.

Now multiply from 10 backwards:
3 x 10 is 30 (Keep going), 3 x 9 is 27, 3 x 8 is 24
3 x 7 is 21, 3 x 6 is 18, 3 x 5 is 15, 3 x 4 is 12
And 3 x 3 is 9, and 3 x 2 is 6
And 3 x 1...
What is it?
Three
Yeah. That's a magic number

A man and a woman had a little baby
Yes, they did
They had three in the family
That's a magic number

(Note: Italicized is for the album version. The TV version is not)