Hey guys I finally finished this thing! It is a 16 bit calculator that displays its answer in complete decimal instead of hexadecimal. It only adds and subtracts at the moment, but I may update it with more features in the future. The parts of it are color coded. The subtractor is the light green wool, the adder is the light grey, the input bus is orange, the binary to bcd decoder is light blue, the output bus is green, then finally the BCD to 7seg decoder and screens are the last part. The key part to this machine is the BCD decoder. It adds the proper amount to the binary inputs to make it show the right numbers on the screen. This works with an equation called double dabble, search it on wikipedia. So when i put in ten, instead of showing 1010, which will not process in a normal decimal decoder because there is no output greater than 9 (1001), it will add 6 to it to show the binary for 16. That means it will output 10000 there will be 0001 on the second screen and 0000 on the first screen, or in short the number ten. The only problem is that numbers 20-29 need 12 added to them, 30-39 need 18, 40-49 need 24, etc. So that is why there are so many of the same unit stuck together. It is split in half and stacked on top of itself in the middle to save space. The machine is kind of slow, I tried using instant wire, but the pistons kept glitching and getting stuck, so for now I am willing to tolerate its speed. Have fun with this guys, and if you have any questions just ask me! :)

OH, and also, many thanks to ohmganesha and his instant ripple carry adder. It is a great adder, and very fast, you can find that here! www.planetminecraft.com/project/fast-adder-using-instant-ripple-carry/