Counting 1-20

Jayden is still learning in expanding his counting skills.. Here is what he has acquired:
1, 2, 3,.......................10, 11, 12, 14, 15 (five-teen), 16, 17, 18, 19, 20.

As usual, number 13 is always missing, and number 15 is always pronounced as "five-teen". LOLs