Hello

Im trying to use a formule in a module from zoho CRM to calculate the profit from a trip. The trip profit is the client cost - hotel cost - transfer cost. The formula I am using is the following:

Tonumber(${Itineraries.Cost to Client}-${Itineraries.Lodge Cost}-${Itineraries.Travel Costs}-${Itineraries.Additional Costs})

This doesn't seems to work as nothing is being calculated and the field just remains empty even after I have added all the number for this calculation.

any help as to the correct formula that I should be using?

Thanks