# Homework Help: 4 Bit Calculator

1. Oct 31, 2011

### ammar93

Hi!
This is a great forum and I've been using it for help for a while so thought I would finally sign up. Anyway my group is making a 4 bit binary calculator for a course in my second semester and we're am having a few issues. The main restriction is that we can only use basic gates to implement the circuits.The adder/subtractor circuit is covered and we have a general idea about the multiplication circuit, but haven't been able to figure out the division circuit at all.

Now my first question is related to the multiplication circuit. I was able to make my own 2 bit version but couldn't figure out 4 bit so after a bit of searching I came across this: http://sit.iitkgp.ernet.in/~coavl/images/cm.png
I don't quite understand how the carry forward works in this circuit though. There seem to be about 64 gates in this...and that would probably be kind of difficult to solder. So is there a way to simplify this circuit more? or at least to decrease the amount of ICs we would have to use?
Secondly, could someone give me a general idea of how a binary divider circuit would work? I've been searching for a long time but haven't come across anything that I can understand.

I'm really sorry for the wall of text but I'm quite confused about how those two functions are going to be implemented. Oh and sorry if this is in the wrong subforum.