If you’ve suffered around computers for any length of time you may notice that the letters A through F are often included with numbers 0 through 9. It’s no coincidence.

Say hello to something called *hexadecimal*. It has nothing to do with Harry Potter.

Hexadecimal is counting base 16, but you don’t need to be a math wiz to appreciate the concept. Hex is Greek for 6. Decimal is Latin for 10. Put ’em together and you get 16. Big word, little number.

Sixteen is a holy computer number. It’s related to 8 and 2, which are also holy computer numbers. That makes 16 kind of a double-holy number. In fact, the number 16 is very popular in computing. But I shan’t bore you with high tech details.

Suffice it to say, it’s more convenient for computer scientists to express values in base 16, hexadecimal, than it is in base 10. There’s a long explanation for that, which involves binary numbers, but it’s boring. So I’ll skip it.

We humans use base 10 for counting: 0 through 9 are the digits we use, though we start counting at 1 and go up to 10 for the first ten items.

In base 16, sixteen values are used. Like base 10, there are the digits 0 through 9. To represent values 10 through 15, letters A through F are used. That helps keep the values in one column. Long story short: that explains why you see the letters A, B, C, D, E, and F in various numbers associated with technology. It’s hexadecimal!

*Do I need to know hexadecimal?* Nope. Only if you intend upon becoming a computer programmer. Or if you’re a nerd, which would also qualify you.

*Do I need to be able to translate hexadecimal values into decimal*? No. Not even computer scientists do that (though some may recognize “famous” hexadecimal numbers). Your computer’s calculator program may have a mode where you can display values in hexadecimal, should you be curious about them. The Windows calculator can be used to display values as hexadecimal, binary, decimal, or even the weird base 8, called *octal*.

*What was the point of this post?* Just to explain why you see letters A through F in various numbers. Now you know. Go win a bar bet for me!

There are 10 types of people in this world: those who understand binary and those who don’t.

Comment by jamh51 — September 26, 2008 @ 12:41 am

We learned both Binary and Hex in depth last year in our IT applied maths course last year. Very interesting and very logical. We also saw octal a bit too, and now I see all numbers in a new way!

Comment by Mel — September 26, 2008 @ 8:13 am

Octal still seems weird to me. I understand its historical significance, but I don’t think I’ve ever used it. I still can’t “see” an octal number as I can a hex or binary.

Comment by admin — September 26, 2008 @ 8:37 am