Null is being calculated as 1 trowing off the calculation

Ive created a form, and have some calculation form fields.  When I go into the form to test the form its grabbing the NULL value field and adding that into the calculations.  So if someone clicks 4 it actually thinks its 5, but its supposed to be 4, so all calculations are off.  Ive gone into the properties and changed the select field to NULL but its still grabbing that as a 1 value.  How do I stop this from happening?  

Could you please tell us which fields we should select to see what is the exact issue and in which Form Calculation?

More details would mean that we can better understand the issue and help you resolve this in the best manner.

Thank you.