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Video transcript

- [Instructor] We are asked which expression can we use to find the missing number in the pattern? So pause this video and see if you can try this before we do this together. All right, now let's try this together. And the way I would tackle it is I'll try to see, hey, can I figure out the pattern between these numbers? And then I could try to figure out the missing one. So to go from 36 to 45, it looks like I'm increasing by nine, so I add nine. And it looks like to go from 63 to 72, we're adding nine. It's good to make sure that the pattern that you think is happening is happening across all of the numbers that you're seeing. And to go from 72 to 81, it looks like you're adding nine. So I'm pretty confident that to go from 45 to this blank number, I have to add nine. And we see here indeed, choice B is 45 plus nine. This number here, you don't even have to figure out what it is. Some of you might realize it's 54. But this is just going to be this number plus nine is going to go in the blank. So 45 plus nine. Let's do another example. So here's it's a little bit different. It says if the pattern continues, what will be the sixth number in the pattern? Pause this video and try to figure that out. All right, so first let's figure out the pattern. To go from two to six, it looks like we added four. Then we are adding four again to go from six to 10. Then we're adding four again to go from 10 to 14, so it seems like we're adding four every time. And this is the first one, two, three, four numbers in the pattern. So the fifth number in the pattern is going to be 14 plus four, which is going to be 18. And then the sixth number in the pattern is going to be 18 plus four, which is 22. And that's what they want. They want the sixth number in the pattern. So 22 is choice D. Let's do another example. Here we're told the table below shows the number of laps Carly ran around the track each day. Which rule describes the pattern shown by the number of laps Carly ran? So like always, pause this video and see if you can work on this. All right, it seems like every time a day goes by, the number of laps are going up by three. So if you wanted to figure out the next day, let's say day six, you would add three from day five. So the pattern here is to add three.