I think you can use the operators:
=, <>, <, <=, >, >=, & (and), | (or) in expressions, for exemple:
Set local key: "SavedSkore" to (LEVEL > HIGHSCORE ? HIGHSCORE : "0").
Will set the local key "SavedSkore" to HIGHSCORE if LEVEL is superior to HIGHSCORE, else, it will set it to 0 (it is just an exemple)
you could also use a function, have the comparison done inside the function, and return a different value depending on the value ( function.Call() will execute a function, and return it's return value)