Math: hexadecimal numbers

Tutoring math, this is an interesting concept.  Its common application is in computer science.

You might have seen numbers like c6 or e9.  Depending on the context, these may be hexadecimal (aka hex) numbers.  The hexadecimal system is base 16.  It uses the following notation:

decimal hex
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 a
11 b
12 c
13 d
14 e
15 f

Since base 16 requires numbers that would be two digits in base ten, the number system is simply expanded to 15 using letters.

Continuing the logic from my previous post, we see that c6 means

12×161+6×160=12×16 + 6×1=192 + 6=198.

So, c6 in hex is 198 in decimal.

Since 162=256, you can represent any number from zero to 255 with two digits in hex. ff=255, as follows:

ff=15×161+15×160=240+15=255.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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