"Два", "три", "четыре" (and the end of numbers) is used with "ра́за":
Двадцать три раза
Восемьдесят два раза.
Ok, so genitive singular is ра́за, and genitive plural is раз, like the nominative. Thanks.
I am thoroughly offended that "fourty" is counted as a mistake. (No but seriously please fix it)
"Fourty" is marked as incorrect, when I think it should count as an accepted answer with a spelling error. It's an extremely common mistake, and I think the Russian course should focus on teaching Russian, rather than English.