How are these numbers calculated?

Big Games

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

Week of 3/10100.0*Chance in playoffs100.0*Average seed
Wales 22 Ireland 9 -5.3
+0.0
Week of 3/11100.0*Chance in playoffs100.0*Average seed
England 61 Scotland 21 -14.5
-1.0
Italy 18 France 40 -6.0
-0.2
Week of 3/18100.0*Chance in playoffs100.0*Average seed
Scotland 29 Italy 0 In
+0.8
France 10 Wales 18 -3.8
-0.0
Ireland 13 England 9 -0.3
Games Above .500
Chance Will Make Playoffs