Smaller roman numerals before larger are subtracted from the nearest larger numeral.
So, IX (1 10) is (10-1)=9. “LLM” would be (50 50 1000) which would probably be (1000-(50-50))=1000. It could be (1000-(50+50))=900 but that would more correctly be written “CM.”
It would probably be “1000s”.
Smaller roman numerals before larger are subtracted from the nearest larger numeral.
So, IX (1 10) is (10-1)=9. “LLM” would be (50 50 1000) which would probably be (1000-(50-50))=1000. It could be (1000-(50+50))=900 but that would more correctly be written “CM.”