yüzüncü üç

Three hundredth

my try

The right form might be "yüzüçüncü", it means 103th.

What a cute little word.

yüzüncü üç: 100th 3 (like yüzüncü kişi, 100th person)

üç yüzüncü: 300th

yüzüçüncü: 103rd

confusing? easier than "kahdeskymmenesensimmäinen"

No it is simple like counting your fingers.

You are right. The Finnish system is very clumsy. Every single part of a numeral conjugates in number and case. In daily conversations I often use English or Swedish numerals because they are short and pretty but it is my personal idiolect, not a common practice.

the hundredth three

this phase is not meaningless....Imagine someone inspecting a series of random numbers, trying to find out just how many threes (3) are included in the series; after he spots the first 99 threes, the next one is the hundreth three (yüzüncü üç.