Help: Formula for (if both cells contain a number, "error")

[gtswhitt]

I want the user to use one of two options:
D29: enter the sum of single items
OR
D30 thru D76: enter each single item individually that the spreadsheet will calculate sum of in D77.

They cannot use both options.

I have $0.00 as defaults in all cells mentioned for the user to type over.

I have the forumula half working below but end up with FALSE in most situations.

Does anyone have a formula I can copy and paste to replace the one I'm trying to fix? Or hidden formulas in other cells as a stepping stone to another to use?

=IF(D29>0,IF(D77>0,"Errornly use one option"," "))

 

[gtswhitt]

=IF(AND(D29>0,D77>0),"Error! Only use one option"," ")

Someone on my end figured it out for me. Thanks anyways.