Yes, good oxford and cambridge english - aahaa!
Yes Nuttyone: that´s the Distributivgesetz. And I know it, but 11 year old boys do not believe what good old Mom says and do not listen to the teacher and when the classe writes a test the little boy will be very surprised, that the teacher does not only want the right sum, but also see the way of calculation.
I know the phrase. SAG IHM NICHTS DARÜBER.
It´s like "Don´t talk about that (topic) to him.
See you!