Checkbox columns in DataGridView

Question

I have a DataGridView control where 2 of the columns are decimal values. I also have 2 checkbox columns. My question is how do I 1) ensure only 1 checkbox is checked per row and 2) do math that 'links' a the checkbox columns with the decimal columns, do some math, and add the totals (for all the rows). I understand that asp.net and web forms would be easier but that is not possible right now. Would this be on the right track: