 We're going to start looking at arithmetic now, and we'll be working with the same four basic operations that you'd expect. We'll start with a review of arithmetic in decimal, and then we'll see how to perform these operations in arbitrary basis. Addition and subtraction are straightforward to do in any base, but multiplication and division end up being a lot harder. This is largely because we learned to do multiplication and division by memorizing a times table. Since we only learned the times table for base 10, we would have to build a times table for any other base that we want to perform these operations in. So for multiplication and division, we'll primarily be interested in performing the binary because we can use a couple of tricks to make the computation simple. We'll use this information later in the semester when we start building hardware to do arithmetic for us. We'll end up using these same algorithms that we use here, but with some minor twists to accommodate the structures that we have available to us.