I designed a Invoice database. I need to be able to have it calculate the following: if the invoice is over $5,000 then tax at 7%. If the invoice is under $5,000 tax at 6% plus $50. If the invoice is a negative amount then it needs to deduct the same tax as was originally charged. Expr1: (IIf([Amount]<-5000,[Amount]*0.07,IIf([Amount]>-5000,[Amount]*0.06+50,[Amount]*0.07)) this is the formula I came up with, but it does not do the negative amounts correctly. Specifically if the negative amount is like -5020.