please help me build a circuit design for a calculator that functions for addition and subtraction only. this is the program to use: http://ozark.hendrix.edu/~burch/logisim/

anything inside the said program can be used. please help me. I badly need a help. I'm willing to pay in any way I can. please. thank you very much.

 

This sounds like an assignment, so it is in an appropriate section.

We are not a homework service, but we will give assistance with specific questions.

As a suggestion, try reading about the process of binary addition in our Ebook - http://www.allaboutcircuits.com/vol_4/chpt_9/2.html

 

There was an old thread from 2007 that you asked me about in a private message. I don't answer via private message because nobody else can benefit from the reply. You can however copy and paste paragraphs from the old thread if you have specific questions. So far there have been no specific questions only a generalized plea for help. We can't help you if you cannot tell us what you need help with.

 

how can I construct the cicuit for they carry in a BCD addition?

thank you so much for the help. Sorry becuase I'm only a newbie.

 

What technique are you using to reset an individual BCD position to zero after 9 on an up count?