How does HEX work?

Question

HEX is made up of 1, 2,3, 4, 5, 6, a, b, c , d, e...
(And combination of Blue, Green, and Red./?).
So do any of the numbers or letters represent a certain color? Like is there a formula or method to make the color you want. Like if I wanted to make yellowish green, how would I combine things? Or would I ha e to look up CSS colors every time?

Usually I just guess and put numbers and letters to form a random color and hope it's a good looking. I don't even know what color I'm forming.

If you have any ideas how the HEX works, please let me know.
If question is not understandable, let me know that too.

Answer 1

Hexadecimal numbers are widely used in IT. As you pointed out you can represent colours in hex format eg. #FFFFFF

When you want to decypher that number, you have to mind that every colour is made of 3 layers that are blend together. Those are RGB (red, green, blue). When you write #FFFFFF you just point that there is FF of Red, FF of Blue and FF of green. (You can quickly transform hex to dec with google ;) )

Generally when you're picking colours for ur website you can google "css colour picker" and you'll get flooded by websites that let you pick a colour and then will translate it to hex or dec values ^^