"Kucingmu dua puluh."
Translation:You have twenty cats.
Well "Your cat's are twenty" does make sense. It obviously means that your cat is 20, 20 in number. But I do consider the fact that you find this hard because probably your mother tongue did not descended from the Austronesian family of languages. I find this easy because I'm Filipino, I speak Bisaya which is another language different from Filipino but much closer than Bahasan Indonesia.
How about translating it as "Your cats are twenty in number"? If you answer to the question "How old are you?" you can answer "I'm twenty" without always saying "years old"... so it would just feel like you have to write the full sentence out in English while in Indonesian you didn't...
I understand that this structure IS used and even popular in Indonesian, so I don't have a problem in teaching it, and I can understand that the contributors didn't want to simply translate to "You have 20 cats", because that would be "Kamu punya dua puluh kucing"... but with the translation of "Your cats are twenty in number" you would have your cake and you could eat it, too! What do you guys think?