Hello,
Here is a possible solution. There may be a simpler way to do it, but not of my knowledge.
I have created the following table to match your issue:
And a summary table to compute what your are looking for:
To achieve this, do the following
-1- Create a table summary with a single field "summary_id" of type number with no decimals.
Insert only 1 line in this table with value "1" in the field summary_id
-2- Insert a filed "summary_id" in the first table, type "link to another record" and link it to table summary.
Set the value to "1" for all lines of your table.
-3- Go back to summary table and insert the field Pledge1_Total:
Do the same for Pledge2_Total and Pledge3_Total with counting conditions set on respective table1 fields
-4- In summary table, add a formula field "Pledge1-3_Total":
Regards,
Pascal