Yes...this seems fairly straightforward once it's explained ...Jukka Aho wrote:The first part basically says when there’s a genitive attribute, its location in relation to the numeral gives way to either an indefinite or a definite interpretation:
Genitive attribute after the numeral:
Kolme Sibeliuksen laulua.
“Three Sibelius’ songs.”
(Somewhat indefinite at least without further context... could be any three songs written by him.)
Genitive attribute in front of the numeral:
Sibeliuksen kolme laulua.
“The three songs of [by] Sibelius”
(Certainly definite – the speaker knows which songs they’re referring to.)
• • •
The second part says when the subject is a (grammatically) singular NP containing a numeral, the singularity or plurality of the verb affects to the interpretation of the definitiveness or indefinitiveness:
A grammatically singular NP + a singular verb:
Kolme miestä ryösti pankin.
“Three men robbed a bank.”
(Some three men. This is probably new information mentioned the first time.)
A grammatically singular NP + a plural verb:
Edellämainitut kolme viiksekästä miestä ryöstivät pankin viime vuonna.
“The aforementioned three men robbed a bank last year.”
(They’re definite three men now, and usually peppered with attributes – or at
least pronouns such as “these” – which further underline their definitiveness.)

Should I be assuming Finnish is more precise than English when dealing with these "congruency" type statements??? Or, maybe I just don't know Finnish well enough yet....

There are rules in English, for example, for uncountable nouns, which as I recall are more or less similar in Finnish....Uncountable nouns will be singular...
"Some of the coffee is missing" v. "Some of the dogs are missing."
And words like, "each" are, apparently, always singular, though in practice this "rule" is, at least from what I can tell, typically broken...
"Each of the cars IS white." v. "*Each of the cars ARE white." Though, in pracice I think most of us native speakers would say the later...


Then there are the "proximity' issues....
"Are the dogs or the cat fat.?"
"Is the cat or the dogs fat.".....
"Ovatko koirat vai kissa lihavaa?"
"Onko kissa vai koirat lihavaa?"....Are both of these sentences grammatically correct?...

[Edit: Typos corrected....and I think the first lihavaa, at least, should be in the plural partitive.]