I am trying to figure out how to calculate the total from columns in a row. I can get the total right with only one item, but when I get the second item, it sums both.

What I need :

Item CostA CostB Total
001 10 20 30
002 10 30 40

What I Get :

Item CostA CostB Total
001 10 20 30
002 10 30 70

help please. thanks.