This document discusses binary subtraction and multiplication. It provides 4 rules for binary subtraction: 0-0=0, 0-1=1, 1-0=1, and 1-1=0. An example of binary subtraction is shown subtracting 10010 from 10110 with a difference of 00100. Binary multiplication is also covered, noting the multiplier is always 1 or 0, and the 4 basic rules are: 0x0=0, 0x1=0, 1x0=0, and 1x1=1. An example of binary multiplication is shown multiplying 10001111 by 1101000 to get a product of 1101.