# The mathematics behind Over/Under Pricing with Integer Goals

I'm trying to understand whole number goals in Over Under betting.

They are described as follows:

https://betdaqhelp.custhelp.com/app/answers/detail/a_id/157/~/what-are-under%2Fover-markets

I am happy that I am calculating the bets with fractional goals numbers correctly. I calculate the probabilities of each score. Then for 2.5 goals I sum up all goal combinations that are <= 2 goals, this is the under, similarly all goal combinations more than >= 3 is the over.

What I'm unsure about is the case where the number of goals has an integer value say 2. In this case if the total number of goals is 2 then the stake is returned. So as before the over is all goal combinations that are 3 or more, but this time the under is all goal combinations that strictly are less than 2. I'm pretty sure this part is correct (but do correct me if I'm wrong). What I want to check is that I should re normalise these probabilities i.e. over/(over+under) and under/(over+under). This is necessary because the outcome total goals=2 is no longer possible.

Thanks

Baz