Hi, I'm very experienced with redstone at the level that I wanted to start a project like this, so I have no idea where to start... I know how to make a 7 segment display, adders, counters, all gates etc. but I could still need to learn how to make a more compact version of the 7 segment display because mine take up a big space. I've seen a 5x3 segment display using a piston tape, but when I tried it, it conflicted for each number
I do not know binary or unary, I have no idea what that is so if someone could explain it to me, It would be highly appreciated.
Okay, I recommend watching videos. Some people here in the forums might help, but videos make it a lot easier to understand. Although, if you have a server i might be able to help you. Just PM me and I can teach you. I don't know everything about a calculator but I can give you a good idea of how it works, how to make one and this sort of stuff,
From my experience, people who say, "I know a lot about redstone, a calculator would probably be a good project!" have less sucess at this that people who say, "I know how to make a calculator, let's see if I can pull it off in Minecraft!"
But if you want to try, I won't stop you. A good way to go about building this (with MCedit's help, of course) is to make your world, then keep making individual components and improving each one, and eventually linking two together, finding the best way to do that, then building 3rd level structures, before linking it all together. Then you just have to program it, which should be easy.
Some good parts to start with: Full Adder, 7-Segment Display decoder, Binary to Decimal decoder, D-Flipflop array.