It sounds like you need a formula that does something like Subtract Col1 from Col2 and then check to see if it equals Col3.
The formula would sound like, "If Column1 minus Column2 equals Column3, then put 'Yes' in this column, and if not, then put 'no' in this column."
The formula would look like this
if (:Column 1-:Column 2 == :Column 3, "Yes", "No")
JMP Systems Engineer, Health and Life Sciences (Pharma)