Probability: What Is Expected Value?

You play a game in which you roll a fair, $6$-sided dice. If you roll a $1$ or $2$, you will receive the face value of your roll (so you will receive one dollar if you roll a $1$, and two dollars if you roll a $2$). If you roll a $3$, $4$, $5$, or $6$, you lose one dollar. What is the expected value of your payoff after one roll of the dice?