Why not make my original one better, faster, easier to use?
Original version: http://www.planetminecraft.com/project/redpower-2-pre-realease-6-calculator/
This thing was a monster to build, 9fps at the lowest when facing the decoder. Very frustrating to deal with but I finished and here it is.
User area has:
-0 to 15 number pad
-Number switching (I wish i can get rid of this but to lazy)
-Operation switcher (x,+,-)
-Binary output display
-Decimal output display (shows final answer, first number, and second number)
-Manual binary input for bottom display (to turn binary to deciaml with ease)

Calculator components:
-8 bit memory
-Decimal-binary for input
-Adder/Subtractor that handles negative numbers
-Multiplier
-Meters and meters of wiring
-A giant decoder for numbers 0-255 and also decodes for the 3, 7-segment displays
-Two much smaller decoders for 0-15 displays
Warning: Use at your own risk, Engineer202MkII is not resposible for crashes, meltdowns, and destruction of your computer.
(I get 9 fps when facing the displays)