Decimal is hex, hex is decimal. In fact, we humans have made up decimal/hex notation cause it is easier to read in certain situations. Basically, 0xFF is the same as 255, just in a different format. EXACTLY THE SAME. If 0xFF was in a register, the register would already contain 255, cause it is the same thing. Many people think that if something is in hex, it cannot be decimal unless converted in a special way, nothing is further from the truth.

Continuing on...
How would we display characters if everything was just a number on the computer? We just say that A is one, and B is Two and so on for all the characters, uppercase and lowercase, and backspace and everything.

But if there was no standard code, things would be haywire. People would have to recode everything and relearn each new system of coding the numbers. So there was this code that would be implemented into every computer, all of the letters and numbers required are the same. This is ascii, where numbers represent numbers. Look up the tables online, there should be plenty.

I think that is all of it...