Learning Challenge: ZX Spectrum machine code: Day 19

Day 19 and it's time for bitwise arithmetic. I've had many years to learn this, but I love the way Toni Baker addresses what can be a rather challenging topic. Instead of trying to teach decimal to / from binary conversions she instead opts to tackle this with binary and hex conversions. I think this is a much better approach as it pulls out a needless step in the process of understanding binary / hex numbers. Add to that the usual AND, OR, XOR, and 2s complement and you have pretty powerful tools for manipulating binary numbers. The next section covers rotating binary numbers. I can't wait. :)