The document introduces hexadecimal numbers, which use base-16 numbering with 16 unique symbols (0-9 and A-F) to represent bytes of data more concisely than binary. It describes how to convert decimal numbers to hexadecimal using integer division and remainders, and how to convert hexadecimal to decimal by multiplying each digit by successive powers of 16 and summing the results. Step-by-step examples are provided to illustrate converting the decimal number 837 to hexadecimal 345 and the hexadecimal number 58B to decimal 1409.