 Okay, so we've talked about the rational number set, and I mentioned that the most important thing about the rational number set are the prime numbers. Because the prime numbers allow you to manipulate to work with all the rational numbers, okay? Now what are prime numbers? Prime numbers are natural numbers that divide evenly, only by one in themselves, okay? So we've got prime numbers. Now one is not considered to be a prime number. So we'll avoid writing down as a prime number, but you can think of this prime number if you want, not a big deal. As far as you're concerned in high school, one can be a prime number or can't be a prime number, it's irrelevant. So we'll start with number two, okay? So your prime numbers are two, three, five, seven, eleven, thirteen, seventeen, nineteen, and so on. So all of these numbers, they can only be divided by one in themselves evenly. So if someone asks you a question, you know, I ask my students, how many numbers are there between one and twenty? I mean, in general, almost everyone says twenty numbers, but there aren't really twenty numbers because every other number that is not a prime number is made up of prime numbers. So for example, if we write down, we've got one over here, right? You go two, three, four. What's number four? Number four is just two times two. So it's not a new number. Number five is a prime number. Number six. Number six is two times three. Then you've got seven. Then you go off to eight. Eight is two times four. Four is two times two. So again, eight is not a new number. And then you've got nine, nine. Nine is three times three. So if you do this all the way up to number twenty, you're going to find out there aren't twenty numbers. There's only nine numbers, okay? One, two, three, four, five, six, seven, eight, and number one. Okay, that makes nine numbers. Now think of the power you're going to have when you're dealing with large data sets, if you're able to break everything down to their prime numbers. So for example, between one and twenty, there's nine numbers. Well, the higher up you go with the number set, with the natural number set, the number of prime numbers decreases. So if you had ten thousand numbers, maybe you could crush that down to five hundred prime numbers. So all of a sudden, you don't have a ten thousand set, ten thousand number set. You've got only five hundred you have to deal with. Now if you take that even higher, let's say you're dealing with a million numbers. Well, there aren't really a million numbers from one to one to a million. There's maybe a few thousand numbers. So that gives you a certain amount of power to be able to work with number sets and break things down. Now this becomes super important, breaking down numbers to their tree, to their prime numbers when you're dealing with fractions. Because what you do is you start cancelling off the prime numbers from the top and the bottom. But we'll talk about that when we deal with fractions. Now, keep this in mind. I'm going to put on some exercises in my website where I'm going to ask you to break down numbers. Now go through those exercises and break them down into their prime numbers. Good luck.