How to tell time in Russian

Did you know that you need to use Genitive case to tell time in Russian?

To do so, you need to name an hour and then add (1) час, (2, 3, 4) часа or (5+) часов and (1) минута, (2, 3, 4) минуты or (5+) минут.

For example:

15:30 – три часа тридцать минут

18:05 – шесть часов пять минут

01:20 – (один) час двадцать (минут)