Here are the numbers, from 1 to 20 in American English. You can also listen to the numbers in British English here below.

One, Two, Three, Four, Five, Six, Seven
That's the way they start
Eight, Nine, Ten, Eleven, Twelve
We'll learn them all by heart.
 
Thirteen, Fourteen, Fifteen, Sixteen
They're the next along
Seventeen, Eighteen, Nineteen, Twenty
That's the Number Song

1, 2, 3, 4, 5, 6, 7, 8, 9, 10
11, 12, 13, 14, 15, 16, 17, 18, 19, 20

One, Two, Three, Four, Five, Six, Seven
That's the way they start
Eight, Nine, Ten, Eleven, Twelve
We'll learn them all by heart.
 
Thirteen, Fourteen, Fifteen, Sixteen
They're the next along
Seventeen, Eighteen, Nineteen, Twenty
(That's the Number Song)