Pages & Numbers will mot update

I'm guessing that you migrated from a previous Mac & earlier versions of the apps were migrated. I had the same problem & I think it could be because I migrated from High Sierra & had Pages 8.1 & Numbers 6.1 installed. I ended up having to delete the apps - Pages, Numbers & Keynote - & then download them again from the Mac App Store.

Did you launch the Mac App Store, and sign in with the same AppleID that you associated with the new Mac? Did you click on your user name in the lower-left corner of the Mac App Store, and on the resulting panel, click on the respective Pages & Numbers to activate them?