School need help using the SUM function

School need help using the SUM function

My school has started using Zoho Creator to keep track of student. Works good but, it needs a tweek.

1) Students are tracked by their student#. How do keep a running SUM of the their number of demerits?

2) More advanced. If a student goes without a demerit for 2 weeks, they lose one. Then they lose 1 for every additional week after. How would I script for this?

Here's a public version of the page
https://creator.zoho.com/ap00/student-demerit-report/form/2/


Any help would be greatly beneficial. Thank you for your time.