Sounds like maybe you're in Manual Calculation.

go to Tools - Options - Calculation and ensure it is set to automatic.

"tunnel engineer" wrote:

when I have 2 populated columns I atempt to drag a summation function in a
third column but all numbers in the 3rd column are 0 untill I click on an
idividual cell and hit enter. Once I click on the individual cell and hit
enter then the summation function works. Do I have a setting off or somethin?