Hi @Sarah_Arminta ,
This post talks about the same issue:
https://community.coda.io/t/checkbox-count-in-a-table/6395
I tried to recreate @Nick_HE 's solution:
To count the checkboxes in the row, you can actually just add them up.
=CheckboxColumn1 + CheckboxColumn2 + CheckboxColumn3
here, but ran into an interesting condition where it works in one row but not another: