These lines work the same as NBA spread bets. In this case, a plus and minus sign denotes whether a team is the favourites or the underdog. These numbers are usually presented with increments of half a point. Here is an example; if team A has -3.5, it means they are expected to win by 3.5 points. However, if they have +3.5, it will mean that they will lose by 3.5 points.