How can I have a field value that is the sum of other (decimal) field values? I have created a custom content type with three decimal fields. I need to tally these three fields and then wrap the output of each one with a specific data attribute,  stating their respective value as a percentage of the total.

Am new to drupal so if someone could point me in the right right direction as to how best achieve this it would be much appreciated.
This question is tagged with Views, so I'm just going to go out on a limb and leave this here just in case: Views Calc


  This module adds simple calculations to a views table. Requires the
  Views module.
  
  You can SUM, AVERAGE, COUNT, MIN, MAX, or AVG selected columns. A plug
  in theme makes the view look more spreadsheet-like (right justifies
  numeric fields, shades calculated columns and rows, and underlines
  calculated rows).