A very good friend had a birthday recently. She thinks she is 37, but I assured her that she is actually 25. In hexadecimal.
When you think of the number 37, those two digits mean 3 tens, plus 7 ones. But there are other ways to express numbers. Instead of having the first digit represent 10’s, you can have it represent any number you want. One that is particularly popular with computer geeks is 16.
When you use the first digit to say how many 16’s you have, that’s called “hexadecimal” (or “base 16”).
So if my friend is 25, that means she is 2 sixteens, and 5 ones.
This is a great way to represent ages as long as the ones place is less than 10. I’m 46 in the usual base 10. So that means I’m 2 sixteens and 14 ones. But we don’t have a digit for 14. So computer folks use letters. A for 10, B for 11, and so on. That means I’m 2E. Next year, I’ll be 2F, and then I’ll finally turn 30.
Homework: Compute your age in base 5 and feel a lot older. (Hint: My friend is 122.)