DIY Calculator

This utilizes a Arduino Nano to handle all the inputs and converts the BCD to usable 8-bit parallel for a Simple Cascaded 8-bit Arithmetic Logic Unit (ALU) Which can display its outputs on a BCD 7-Segment Display. This Calculator features just Addition and Subtraction which is achieved through the One's Complement. So far, I've only managed to get the Nano working and the Adder part of the ALU. I haven't had the mind to work on the Memory part of the system because of some issue's with preplanning and also running out of budget to get new components. Currently stuck on the Memory phase of the project where I store the inputted and calculated numbers into 3 pairs of 74ls245N's paired with a 74LS273N But I'm mostly here to share my journey and also get some help along the way to finish the project!