"The four girls read four books."
Translation:As quatro meninas leem quatro livros.
Here is a great explanation from Sonia Portuguese (because it is more complicated than just the first two numbers):
However, in your example:
- mas quarto meninas*
You used "quarto" (instead of "quatro") which is "fourth" (or, "room") and is an ordinal number, and PT ordinals do agree with gender and plurality of the nouns they accompany:
Duo however, usually makes us spell out numbers, even ordinals so it can tell we are getting it.
There are a couple videos and charts at the original site linked above to explore further.
Do you disagree then with this:
200, 300, 400, 500, 600, 700, 800, 900 have feminine and masculine forms. They must agree in gender and number with the noun. Observe that when they are written in the masculine form they end in “os” and when they are written in the feminine from they end in “as”
• 200 men: duzentos homens / 200 women: duzentas mulheres
• 330 cars: trezentos e trinta carros / 330 houses: trezentas e trinta casas.
• 467 boys: quatrocentos e sessenta e sete meninos / 467 girls: quatrocentas e sessenta e sete meninas.
I mean, I would be happy if it is only "1" and "2" I have to worry about... =]
Oh! There you go again, getting my hopes all up then dashing them against the cruel rocks of the Portuguese language rules. =(
To be brutally honest though, I really had not given much thought to 21, 22, 31, 32, 41, 42... until your recent post here so I did learn something. :)
As quatro meninas = The four girls
These are specific girls who are reading books.
Os quartro livros = The four books
That would imply that only four books were available for the girls to read and they are specific books, not four books out of a hundred to choose from, or four books at the library, or four books over the summer (for instance).
The Duo translation is that, "the four girls read four books" which means specific girls read non-specific books.
When it comes to using articles then it makes more sense to ask for consistency (and use of them, at least in all the Portuguese outside of Brazil). But these are not possessives in this discussion's exercise which otherwise would look more like this:
- [As] minhas quatro meninas leem [os] teus quarto livros