How are these numbers calculated?

Big Games

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

Week of 4/4100.0*Chance in playoffs100.0*Average seed
Winder Barrow H 2 Apalachee High 3 +37.0
+0.7
Winder Barrow H 0 Clarke Central 4 +10.0
+0.1
Week of 4/12None
Week of 4/18100.0*Chance in playoffs100.0*Average seed
Apalachee High 5 Flowery Branch 3 In
+0.3
Flowery Branch 1 Cedar Shoals Hi 0 -2.8
-0.0
Heritage High S 5 Loganville High 2 -0.1
-0.1
Points
Chance Will Make Playoffs