Sorry if this is the wrong place for this info. I am off course not going through every mistake I find, but this one was during an explanation.

In Unit 4 - CSS: An Overview, it states in the explanation part: Hexadecimal counting is base-16. Each digit can be the numbers 0 through 9 **or** the letters a through f! Crazy, right? Check it out:

Shouldn’t that " **or** " actually be " **and** " ? As far as I remember that “a” represents the 10, etc…