"How much money for the farm gear?"
Translation:ʻEhia kālā no nā lako mahiʻai?
Frustrating, yes. I did wonder how it would go since "gear" on this sense is singular in English no matter how much stuff their is. I used "ka" which was accepted but ka was tagged as a typo with nā as correct. All I can say is, in English, that CLOTHES is a plural word that is treated like a group, and so gets treated like a singular. And CLOTHING is a singular word that is treated like a plural. So you have to say "a piece of clothing" to mean singular.
I stumbled over the same problem. I explained it to myself it must be a non-native speaker problem (English not being the language I grew up with) cloth, I learned is singular and clothes plural. Now in Hawaiian the article points to different things, nā as plural and ka for singular or when it is a given that a certain thing is more then one and that is where my brain is taking a brake everytime, sees it is the plural form in English and gets the article wrong in Hawaiian. Work in progress ;)