Hexadecimal Math Review

This was something I really wanted to go back to as math is always scary territory, however just like subnetting this is something I always wanted to master for the CCIE. So here we go..

Training material used ‘The Bryant Advantage Hexadecimal Conversion Workbook’

Basic Hexadecimal values:

a = 10
b = 11
c = 12
d = 13
e = 14
f = 15

Conversions

Hex numbers are read in units of 16.

Always use this table to deal with the math:
Units of 256 – Units of 16 – Units of 1

Hex to Decimal Example:

1C in Decimal? Well we know that C in decimal is 12.. so here comes the math bit..
Units of 256=0 – Units of 16 = 1 – Units of 1 = 12
and therefore 16 units of 1 = 16 + 1 Unit of 12 = 28
 
So 1C in decimal is 28!

Decimal to Hex Example:

13 in Hex? Well this is easy as we know that 13 = D So 13 in Hex is D

Something more of a challenge… What is 784 in Hex?

Units of 256 =3 – Units of 16 =1 Units of 1 = 0 = 310
(256*3=768 leaving 16..)
 
So the decimal number 784 in hex is 310
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