One of my favorite bits teaching Hex Ed was writing it on the board and saying it out loud:

0 - Zero
1 - One
2 - Two
3 - Three
4 - Four
5 - Five
6 - Six
7 - Seven
8 - Eight
9 - Nine
A - Ten
B - Eleven
C - Twelve
D - Thirteen
E - Fourteen
F - Fifteen

It is so hard writing the letter and saying the number.