Can someone help me with an operation for adding two columns of a table together?

I feel that this should be a fairly simple code, but I seem to be having problems. I have a table with 2 columns. Each column has 64 points. I need to add point 1 from column 1 to point 1 from column 2, then point 2 in column 1 to point 2 in column 2, all the way to point 64. I would like to do this with out having to add each one individually, so I was wondering if anyone had an operation to do this. I also would like to display the results in the third column of the table just for an easy way to compare all the points.
Thank you for your help!