excel 2010 automatically fills in cells

[kylefoley76]

I'm using excel 2010 for mac and on one spreadsheet in one column i have the formula

=IF(F3899<>"",(E3899-E3898)*24,"")

it will automatically calculate the value in that cell when i put in the values in column e and f

on another spreadsheet i would also like it to do that automatically but i'm using the formula =H11-I12
and that column is H. excel won't do that column automatically

 

[VoG]

Maybe you need to convert the second sheet to a Table, like the first one seems to be.

 

[kylefoley76]

how do i do that?