FileMaker is a database. Not a spreadsheet program. It's internal structure is quite different and thus the same methods for referencing data are not found in both systems.
How to do what you describe depends in great part on how you design your tables and relationships in FileMaker.
Your expression appears to subtract cell H9 from cell k8 and add it to cell j9. It then seems to compare that value to a different expression referencing values in cells k9, h10 and j10. Does that mean that you want a Boolean value returned? True if the two expressions evaluate to the same value and False if they do not?
A more detailed description of what you want to accomplish would help us to help you.