How to pronounce ten, twenty, thirty and thirty?

Ten, twenty (niàn), thirty (sà) and thirty (x) are the combination forms of numbers in ancient Chinese. Where "e" means "forty". Whether there are combined characters like 50 and 60 is not exactly recorded. I guess it's because numbers are not often used since 50, and they are not as frequent as 20 or 30 from the perspective of calculating calendar days or compiling volumes, so it's not necessary for the ancients to create so many rare words. Bottom line: Language serves human social life, doesn't it?