Type the = sign, then go to the other sheet and click in J6, then hit the +
sign, and go to the relevant sheet and click in G21. Hit enter.
You should have a formula that looks something like
=Sheet2!J6+Sheet3!G21

Signature
David Biddulph
> I've tired =j6+g21 but from different sheets, so its possible when i
> change
> one the other changes also. What formula do I need, because thats just not
> working