Simplifying and Evaluating: what is the difference?

Can you tell me what the difference is between simplifying and
evaluating, in algebra, and can you give examples?

It just depends what the problem looks like.
Usually when you are simplifying, you are downsizing an expression or group of terms.
Usually when you are evaluating, you are finding the actual value of a term or group of terms.

Examples:

Simplify the expression:
3x + 2x + 4
= 5x + 4 {combined like terms}

Evaluate the expression, when x = 2
3x + 2x + 4
= 3(2) + 2(2) + 4 {substituted 2 in for x}
= 6 + 4 + 4 {multiplied}
= 14 {combined like terms}

- Algebra House