How to get a magic number.

Here is the magic numbers as things stand right now.... The suns have to go 12 - 6 (HAVE to beat the Mavs the next time they play) .... The Mavs would have to go 7 - 10 Losing the match up with the Suns

Maybe im wrong?

Games Behind; the formula is ((first place W - teams wins) + (teams loses - first place L)) / 2, Just work backwords. I will spare you my math.

Maybe you guys have a different way of doing this?