Hexadecimal is a numeral system with a base of 16. In hexadecimal, each digit has 16 possible values ranging from 0-9 and A-F (0-F in hexadecimal). Hexadecimal is used in computer systems as a convenient way to represent binary data.

In decimal, each digit has 10 possible values. For example, the number 1 has a value of 1. The number 2 has a value of 2. And the number 3 has a value of 3. Similarly, in decimal 10 is equal to 1+0+0=1 and 12 is equal to 1+2=3. This system makes it easier for humans to express numbers because there are ten digits on a hand and 10 fingers. But in binary, each digit has two possible values. For example, the number 5 has a value of 1+0=1 and the number 6 has a value of 0+2=2. This system makes it harder for humans to express numbers because there are only two digits on one hand and two fingers.