I don't know if you can do it in Norwegian, but in colloquial Polish it's possible to specify how much time will pass until the next full hour without specifying what hour it is.
So, it's possible to say, for instance: „Jest dwadzieścia po” [It is twenty past X] or „Jest za dziesięć wpół do” [It is ten till half X], regarding your first example.
So, it's possible to say, for instance: „Jest dwadzieścia po” [It is twenty past X] or „Jest za dziesięć wpół do” [It is ten till half X], regarding your first example.