for the numbers below how do yougo about: 1)computing the total Contribution Margin.

Please help help with figuring out how to work through the following answers:

for the numbers below how do you go about:

1)  computing the total Contribution Margin.

2)     Computing the Operating Income under Variable Costing.

3)     how do you develop a reconciliation from the  Variable Costing Operating Income to compute Operating Income under absorption costing.