In a list of assessment data I have current test scores in column L and the
previous test score in column G. I have a formula that works out the
difference between the 2 scores... =IF(L120,L12-G12,"") into column M, but
this returns #N/A if no test result is entered into column L which is causing
problems when I'm trying to record a macro to automatically sort data. I have
tried to change the formula to lose the #N/A but am having to admit defeat!
Data looks like this

G L M
14 15 1
14 13 -1
14 14 0

Any help greatly appreciated!!
Mrs T