I don't understand why this question has been closed as unclear. On the contrary, when I read it, it seem completely obvious and multiplying circuits are a more or less common topic. It gives a bad impression about the people who decided to close a question when it just seem they were the one unable to understand...
(Edit) : Since there are two answers and I want to reply this to both, I will do it here.
Both mention not wanting to solve homework problem... I agree with the principle of not solving homework problem, but this question have been asked 2 years ago and this aspect is now out of scope and stackexchange is intended to provide quality content for ALL users and not only for the asker. In this regard, when the homework situation is invoked, I believe we might delay the answer for a few week or months or even on year, but not close it.
I found this question by googling on the same problem, and this situation is quite frustrating - and by the way, this is not the first time I see such a situation and it was not usually because of the homework context but gave more of the feeling people didn't understood or even in some case, that they down-voted it by frustration that their over-simplistic answer was not accepted