Oh!  I didn't catch that the - symbol was meaning minus, I misread it as a break in the sentence.  hahaha

Your comment makes a lot more sense than mine when taking that into account.

Thank you so much for your responses. I tried this formula and it did work but not quite right. The calculation is not done correctly. It should equal out to 0 but its not. Also, I had to fill in all the fields to get the answer. Is there a way to leave one of them blank and it would just count it as zero?  Thank you!

Is it possible there is a typo in your formula?

I just made a test form similar to yours.  I used the formula names in the labels too, so you can match them up to the formula easier.  I'm getting a total of zero.

Here's the formula I'm using:

=grand_total-SUM(all_credit_card_charges,cash_advances,personal_expenses,city_check_issued_reg_fee)

Regarding the second part about leaving some fields blank...

I don't see the same behavior, maybe a difference in behavior between versions or something - but in situations like you describe, where a calculation is not liking a blank value, and you would like to use a zero instead, then I like to use IF statements to do that.  IF(all_credit_card_charges="",0,all_credit_card_charges)   If all_credit_card_charges is blank, return a zero, otherwise return the value of all_credit_card_charges.

Then it'll allow blank values to be excluded from the calculation.

Here's the same formula, modified to utilize IF statements for each variable.  The line breaks and extra spaces are there for readability and can be included or excluded as you like.

=
IF(grand_total="",0,grand_total)
-
SUM(
  IF(all_credit_card_charges="",0,all_credit_card_charges),
  IF(cash_advances="",0,cash_advances),
  IF(personal_expenses="",0,personal_expenses),
  IF(city_check_issued_reg_fee="",0,city_check_issued_reg_fee)
)

IF statement worked perfectly. I still have an issue with calculation. All the values in the fields come from the tables above so the submitter enters the values in the tables and not just in the field. I think the problem is with city_check_issued_reg_fee field. Submitter enters the amount in the field at the top of the form and then I just use that field in the grand total and in the separate city_check_issued_reg_fee field. For some reason it uses that value in the grand total but it doesn't subtract it in the city_due formula that I use. Sorry for such confusion. 

If the formula inside the city_check_issued_reg_fee field is working as you expect, I don't think it should be failing further into the process when calculating into the city_due field.

Can you share the variable names and formulas for all 6 of the fields?

I used Java Script to calculate the value for the fields so I do not have formulas for them I have css class for each.