How are these numbers calculated?

Big Games

How we did last week and who we should root for this week.   Explain

Week of 1/4100.0*Chance in playoffs100.0*Average seed
Newcastle 2 Adelaide 1 In
Brisbane 1 Melbourne 2 -0.5
Wellington 0 Sydney 2 -0.1
Perth 1 Central Coast 1 +0.1
Week of 1/11100.0*Chance in playoffs100.0*Average seed
Brisbane 0 Sydney 0 -0.1
Central Coast 1 Newcastle 2 -0.0
Week of 1/18100.0*Chance in playoffs100.0*Average seed
Adelaide 2 Brisbane 0 -1.0
Newcastle 2 Perth 1 -0.3
Central Coast 2 Wellington 0 -0.1
Sydney 2 Melbourne 2 -0.1
Points
Chance Will Make Playoffs