Let's do some examples creating picture and bar graphs. So it says Mr. Smith assigned a special project about the ocean to the students in his Earth Science class. To find out if students who spend more time on their projects got better grades, he asked the students how much time they spent completing their projects. Create a bar graph to show how much time each student spent completing the ocean project. So James spent 36 minutes. So I'm gonna click here and I'm gonna move this up to 36. Eji spent 54 minutes. So I'm gonna move this up to 54 minutes. Then Minli spent 36 minutes. So I'm gonna move Minli up to 36 minutes. Then Simone spent 30 minutes. So I'm gonna move Simone up to 30. Then Kiran spent 12 minutes. So I'll move Kiran up to 12. And there you go, I have constructed the bar graph. Let's do a couple more of these. All right. So on Thursday, Ming went to see a loud and exciting performance by the Dinosaur Orchestra. Create a bar graph to show how many of each type of dinosaur were in the Dinosaur Orchestra. So I guess there were 42 Stegosaurus's. I don't know if that's a plural for Stegosaurus. So there are 42 Stegosaurus's, 63 Raptors. So we move the Raptor up to 63. 35 Triceratops. Then you had 49 Tyrannosaurus. 49 of these. So fairly straightforward. So let's do a couple more of these. All right, so now it tells us Rose's flower shop makes bouquets for special occasions. Each bouquet comes with a different number of flowers. Create a picture graph to show the number of flowers in each bouquet. So this is kind of like a bar graph, but instead we're gonna use pictures. Each picture shows a certain number. So in this case, a picture of a flower represents three flowers. So the Mother's day bouquet has 21 flowers. So 21 flowers. Now you might be tempted to put 21 pictures of flowers here, but you have to remember each of these flowers represent three flowers. So one way to think about it, you could count by threes. Three, six, nine, 12, 15, 18, 21. So that over here, this right over here, would represent 21 flowers. And you notice I just made seven of this picture, and that makes sense because seven of these pictures, and each of these pictures represent three flowers, seven times three is 21. The Mother's Day bouquet has 21 flowers in it. All right, the Anniversary bouquet has 27 flowers. So three, six, nine, 12, 15, 18, 21, 24, 27. I have nine flowers here. Nine times three is 27. The Birthday bouquet has 18. So three, six, nine, 12, 15, 18. And I just made six pictures here because each of them represent three flowers. Six times three is 18. Then finally, the Congratulations bouquet has 12 flowers in it. Three, six, nine, and 12. There you go. I think we're done. I think we're done. Let's do one more of these. All right. Barry Bee and his bee friends love to pollinate flowers. They created a chart and a picture graph to show how many flowers each of them pollinated today. Use the information in the chart to answer the question about the picture graph. So it says, On the picture graph, each flower equals blank flowers, or each picture of a flower, I should say, equals a blank number of flowers. So it says Barry pollinated 27. These are impressive bees that they sit there making charts. Barry pollinated 27 flowers, and they only drew three pictures here. So these three flower pictures must represent 27. So the way that they would represent 27 is if each of these represent nine because we'd have nine, 18, 27. So each of these must be nine flowers. But let's see if that works. So for Bumbly, 63. So let's see, nine, 18, 27, 36, 45, 54, 63. Yep, it looks like it works out. Betty is one, two, three, four, five, six. Six, six times nine is 54. That is the number of flowers she pollinated. Bertie, one, two, three, four, five. If each of those pictures represent nine, then this would be five times nine is 45. That is the number of flowers Bertie had actually pollinated.
Let's say that we run an egg farm, and yesterday, we went out and we collected 398 eggs from the chickens, and then today, we went out and we collected 251 eggs from the chickens. And what we're curious about is, roughly how many eggs do we now have that we've collected over the last two days? Well, there's a few ways we could do that. We could just add 398 to 251, and figure out what that is equal to. But let's say that we don't have a lot of time, and we don't have paper, and we want to do it in our heads, and we don't care about the exact number. We want to know roughly how many eggs do we have? Well, that's where the tool of estimating is useful. So instead of saying the exact amount of eggs, we could say, how many do we roughly have? And that's what this squiggly equal sign means, it means, hey, we don't have to get the exact number, but how many do we roughly have? And so we will be estimating. And the way that we can do that is that we can round each of these numbers to a number that is close to them, but that's easier to add in our heads, and then we add those two numbers. So pause this video, and see if you can do that on your own before we do it together. Alright, now let's do this together. Let's start with 398, and let's round it to the nearest 10. So, 398, you can view this as, we have a nine in the 10s place, but you could view this as 39 10s, and eight. The 10 that it is right directly above is exactly 39 10s and zero ones, or 390, and then the next ten would be if we go up to 40 10s, which would be the same thing as 400. Now, which one would we round to? Well, 398 is closer to 400 than it is to 390, and we've talked about in the rounding videos that you can see that this right over here is five or greater, so we would round the 10s place up. So we would round to 400. And so, 398, we round to 400. And then we're going to add that to 251, what's that rounded to the nearest 10? So I'll do that again, right over here. 251. The 10 that is right below that is going to be 250. The 10 that is right above that is going to be 260. Once again, you could view this as 25 10s and one. And 251 is clearly closer to 250, we can round down. Another way to think about it is, you look at the 10s place, and then you look at the ones place, and you say, hey, this is less than five, so I'm gonna round down to on the 10s place, so we get to 250. So when you round 251 to the nearest 10, you're going to get 250. Now, I encourage you, add these two in your head. What would this be equal to? Well, the way that I think about it in my head, and there's a lot of different ways to approach addition, but you could say, alright, I can think about the hundreds. I have four hundreds, and I'm adding that to two hundreds, and let me do this in a new color. So if I have four hundreds, and I'm adding it to two hundreds, well, that's going to be six hundreds. And if I have zero 10s, and if I'm adding it to five 10s, well, I'm still going to have five 10s, and then I have zero ones in either cases, so I'm still going to have zero ones. And so there you have it. We were able to estimate 398 plus 251 as being roughly 650.
