Trying to create expression field in query

[Buddha1]

I have a table with the following feilds NAME, COMPANY, CURRENT, MONTH1, MONTH2, MONTH3.
I drug all of these fields down into the query and I want to add an expression field that adds MONTH1 and MONTH2 columns in the last field. In the expression builder I put: = [TblMainData]![MONTH 1] + [TblMainData]![MONTH 2]
However when I run the query nothing shows in the field and I now there are numbers in the table under these columns so it should add these but it doesn't. Can someone please help me???

 

[glalsop]

Perhaps Month1 or Month2 can occasionally be null?

Try the Nz function:

= Nz([TblMainData]![MONTH 1]) + Nz([TblMainData]![MONTH 2])

-Gary

 

[Buddha1]

Yes sometimes the fields that will be added are null. I tried = NZ() but got the same results as before??? Is there any other suggestion???