Is it possible to add a table to a form in which the elements in a column can be added?

Dear folks,

Here's what I want to do: I need to add a table to a form that contains two columns.  In the first column you have a five lines for five different tasks; in the second column you have the amount of time for completion of each task.  At the bottom of the second column I want to add a total of all the values in this column.  Any suggestion of how I might be able to accomplish this?

Best regards,

Ulises