Use a master formula Google sheet that other sheets can connect to and use said formulas

Hi,
I have made a Google sheet at work that suggests a grade (A,B,C,D or F) depending on what dropdown values have been selected, this all is working fine.

However, I am interested in knowing how I use a master Formula sheet that other sheets can connect to.

The reason I wish to do this is that each employee (around 30) uses their own sheet that all looks the same but is tied to them. This means any change in code I make, I then have to replicate across 30 or so sheets which can get time consuming and laborious.

So I would like to add my formulas to a master sheet that all the other sheets are connected to, thus allowing for a single update of the code on the master sheet and these changes are then done on the other 30 sheets.

I have a simple formula here =if(D3="F", "Scrap","") that is on my master sheet but when I attempt to take that code onto the other sheets all I get is a string and do not recognize it as a formula.

I hope this makes sense, I did do a search on this before posting this but I could not find anything, apologies if I missed it.

Thanks
Neil

Can you please use this linked file to create a sample of what you are trying to achieve:

https://docs.google.com/spreadsheets...gid=2100307022