how to evaluate 2*1 in a diff cell

I have a column for Length & breath where the value is entered as L*B, and I have a separate column to calculate the area. How do I use the value from the Length & Breath column to solve itself and show the answer in area column. I have tried putting the cell directly. It does not work.

Length & Breath  C2= 3*2   
Area          =C2                       

This does not work

Please do not suggest to use different columns for length & breath as that is not an option.