I wanna an addtion equation for the google script

[TIMAI2]

You should have found Create and Update functions where you found your existing script ?

If not see here for ideas

Simple CRUD with Google Sheets and Apps Script (fixes Hay Kel flaws...)

I have lost count of the number of times the community has received requests for help from developers, after following the Hay Kel series of videos on CRUD with google sheets. The videos are well produced, and offer the viewer a good insight to creating the app-sheet-script ensemble required for CRUD activities. However, the script is flawed: a bound to sheet script, with code that only allows the bound spreadsheet and use of the first sheet; hard-coded columns and hard-coded row data for upda…