Have you heard of the mnemonic PEMDAS? It tells you the order of operations:
Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction.
2-2*2+1 = 2-(2*2)+1 =2-4+1 = -1. You multiply and divide before you add or subtract.
Just out of curiosity, how do you get -3? 1 would be a common mistake.