"I want to exchange currency."
Translation:Я хочу обміняти валюту.
This is a common misconception. Word order is in fact important, it allows to:
- show what constitutes new information («Я» is someone known to the reader, «хочу обміняти валюту» is new information about me; «Валюту хочу обміняти я» would mean 'It’s me who wants to exchange currency’ — i.e. the fact that someone wants to exchange currency would be known to the reader, and the fact that it’s me who wants to exchange it would be new information),
- emphasise certain words by moving them out of their usual place (the noun objects generally follow the verb; so if you move it out of its place, you either emphasise it, or the whole sentence: Я валюту хочу поміняти either means ‘It’s the currency I want to exchange’, with ‘currency’ emphasised, or it can mean that you’re very emotional about exchanging your currency, maybe you’re desperate because you can’t find any bank).
Duolingo generally doesn’t accept non-neutral word orders.
Because it is currency exchange, and not change. You can also change money from coins into banknotes or vice versa - this would be called розміняти. If you want to change money, because your dollar bill is torn or looks dirty and you want to replace it with a better banknote, in the same currency - this would be called поміняти.