I read somewhere that in order to express "over a number of things/people" we can use this pattern: (multiples of ten)+几+classifier+noun like 十几个人:more than ten people (less than 20) However, somewhere else I came across this pattern 几+十+classifier+noun The sequence of 十 and 几 are exactly reversed in these two patterns. I wonder if these two patterns have the same meaning or not?
十几个人 = 10 <= x <= 19
几十个人 = x > 20
So the latter has more people.
Generally, the 几 in the word means that this number can be chosen arbitrarily from all numbers greater then 2, so 几百个人 is 200-999 people.
If you just want to express that there are a lot of people, then you usually put 几 in front to show there is more.
My answer might not be how teachers would explain this typically, but here it is..
When you ask someone 這東西有幾個(几个)?, you can think of 幾(几) as a character that represents the uncertainty of counts.
So for "這東西有幾個", you can view it as "這東西有?個"
Same rule applies to your question:
幾十個 -> ?十個 -> ?0, so it implies you have at least >19
十幾個 -> 十?個 -> 1?, so it implies you have 11~19
幾百個 -> ?00, implies you have at least >100
幾千個 -> ?000, implies you have at least >1000
Same rule also applies when you want to answer:
五十幾個 -> 5? -> 51~59
^ This however only makes sense if the count is under a hundred.
If more than a hundred, then we typically use 多:
五十多個 = 50+
兩百多個 = 200+
兩百幾個 would not make sense