you will have to build a full adder or use a series of and gates to you answer(i don't recommend using and gates they are not really calculators and they take massive space for more bits).

Addition is an XOR with carrying gate, it's not that hard to make. Either google it or look at other saves. I forget what subtraction is, I think it's AND but I'm not sure.

by the way an xor with a carrying gate is called a full adder

@TheTempest (View Post)
Full adder is best, because it allows subtraction as well as addition more easily and it's smaller when you try making the thing bigger. Also, if you need to do multiplication, you can look at my thing, it is kinda confusing and it's huge because I made it ages ago and haven't got around to shrinking it. Really, with that, just shift and add. division...haven't worked that one out yet.

@Vanquish349
It isn't, full adders are more complex, an XOR gate with a carry is a half adder.

Check through my saves, I've got an ALU some where in there.

@jalfor (View Post)
with a carry, half adders have no carry

You could just use some lua scripts to link em to our numpad :P

@vanquish349 (View Post)
http://www.play-hookey.com/digital/images/haddr00.gif

They do, look at this.