"I need six liters of water."
Translation:Potrzebuję sześciu litrów wody.
difference between "potrzebuję sześć litrów wody" and "potrzebuję sześciu litrów wody"??
Although not exactly grammatically correct this form is so incredibly common that the course creators decided to accept it anyway after some time.
This isn't the only big change in that respect. You can also now use "you guys" and "you all" when translating second person plural sentences from Polish to English.