Lock formulas in Numbers to prevent accidental changes

You can lock a spreadsheet (document):

Lock a Numbers spreadsheet on Mac - Apple Support

Or lock an table on a sheet:

Resize, move, or lock a table in Numbers on Mac - Apple Support

Or lock layers and objects:

Layer, group, and lock objects in Numbers on Mac - Apple Support

But you can't lock a formula.

You could move all the formulas you want to protect into a table and lock that, leaving the other tables you use for data entry unlocked.

In general the security provided by locking is limited. It is as easy to unlock something as it is to lock it.

SG