I've now changed it to the 8052 and it's reduced the errors to 2:
Multisim - 04 April 2021, 19:45:13
-------------------------Building: Project: Calculator--------------------------
Note: -E compiler option was not present. This option has been added to the compiler build command temporarily.
Note: -O compiler option was not present. This option has been added to the compiler build command temporarily.
Compiler results: 0 - Errors, 0 - Warnings
Linking...
Error: : 0 psect "rbss" exceeds address limit: 08Ch > 080h
Error: : 0 psect "rdata" exceeds address limit: 08Ch > 080h
Linker results: 2 - Errors, 0 - Warnings