I'm having an issue with formula fields. I want a field that tracks funding we get from partners to help with deals. So what I need is if a partner gives 20k on a deal worth a 100k for the client portion field be populated automatically with 80k So amount-Partner funding. Partner funding is not on all deals so it would be if this field is known. When I try to create this formula I get an error but not understanding why. This is the formula I'm trying. Could any one help to see what I'm missing?