+678 First we have to figure out what 1001011-100110. If you use a calculator (or if you use scratch paper) you get: 900901. Binary is basically base 2. If you know how to convert between base 10 and another base (in this case, it is base 2) this is a rather simple problem; it just takes a lottt of computing. If you compute (it does take a while) you get 11011011111100100101
