Let's say that we're interested in approximating what the square root of 4.36 is equal to. So we want to figure out an approximation of this, and we don't have a calculator at hand. Well, one way to think about it is we know what the square root of four is. We know that this is positive two. The principal root of four is positive two. So you say, okay, this is going to be a little bit more than two. But let's say that we want to get a little bit more accurate.