Maybe this one is easier

Hello,
I am hoping that this problem is easier than the last one I had as no one was able to help me at all. I have a MSAccess 2000 Database with 2 fields, one is titled “DATE” and the other is titled “SALES”. Mutliple dates will be entered into this database with the amount of sales for each date. I have to be able to determine the difference between the sales on date “A” & date “B” i.e. If on 11/1/03 we sold $1,200,000.00 and on 12/1/03 we sold $1,000,000.00, the difference between the two is $200,000.00. Now I can get the query to call up any two dates in the database that I want, but I can not get either the report or the query to subtract the amount of date “A” from date “B”. Can someone please tell me what I am doing wrong please?

Thank you