With some betting sites odds, certain games are priced differently than risking $1.10 to win $1.00 (which is called -110 odds). For example, you might see the Giants priced at -105 and +7 in a game against the Jets. Now, you only have to risk $1.05 to win $1.00. This is obviously better odds, but it's very likely that they will lose by exactly seven to give you a push. Taking -110 and +7.5 with an alternative bookmaker is actually the better bet.
Total: Also called the over/under, it is a number set by the sportsbooks that proposes a number of points that will be scored in the game by both teams combined. Then, fans predict whether there will be more points or less points than the ‘total.’ If you bet the under 41.5, you are hoping for a tough defensive battle with lots of running game. Pick the over, and presumably you feel this will be a high-scoring game. In short, you are predicting whether the combined total score will be more than (over) or less than (under) the total.