Pre-Calculus and what they mean ?

I've read some very informative, plain English definitions on the following Pre-Calc terms, but I still don't understand them and they are the following.

**ABS** (Absolute Value) Takes a single value and returns the positive version of it. Could anyone give me a easy to understand example. :)

**Av, MIN & MAX** - Correct me If I'm wrong but is MIN & MAX adjust where on a graph the curve should be, as for AV I have no clue :(

**SQRT** - Square Root takes a single value and calculates the square root of it. Could anyone give me a easy to understand example :)

*Exponent*: **Pow** (X,Y) This I don't understand.

I hope someone could help me understand the following terms.