In the hexadecimal system, what number comes after 9?

The story behind the answer

In the hexadecimal (base-16) system, digits run 0–9 and then continue with letters A–F to represent values 10–15. So the symbol after 9 is A, which stands for the decimal value 10. Note that the hex number 10 does not come right after 9; hex 10 equals decimal 16 and appears after F.

Hex is common in computing because each hex digit cleanly represents