I think there’s a bug with this sentence. It should say “Nahast’ei” rather than “Nahastei” (sorry I don’t have accents).
Yeah, I suspect this is a typo. I learned nine as náhástʼéí too and that was accepted as the answer for nine in a previous exercise.
6, 5, 4, 3, 2, 1...
This lesson does not say the words