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- [Voiceover] A farmer used fence posts to build a fence for Hazel Horse and Pauly Pony. The farmer used 26 fence posts to build Hazel Horse's fence and 19 fence posts to build Pauly Pony's fence. How many fence posts did the farmer use in all? If you like, I encourage you to pause the video and try to figure it out. I'm assuming you have tried it, so let's think it through together. Whenever you think about a word problem like this, what are they asking? What's the story in our head? A farmer is building fence posts for two different horses, Hazel Horse and Pauly Pony. There's even a picture of Hazel Horse here and Pauly Pony. They look very similar. The farmer used 26 fence posts to build Hazel Horse's fence, so that's these 26 fence posts right over here. These are the 26 fence posts for Hazel Horse's fence. I haven't counted it, but I'll just take their word for it that there are 26 here, and then 19 fence posts to build Pauly Pony's fence. These are 19 fence posts right over here. How many fence posts did the farmer use in all? In all, so what do they want us to do? Do they want us to add or subtract these numbers? Well, they're looking at "in all." How many total fence posts did the farmer use? Well, the total is how many used in Hazel's fence and Pauly's fence, so we should add these two numbers. We're going to add 26 plus the 19, or let me see. The 26 is in that brownish color, 26. That's the 26 fence posts to build Hazel Horse's fence, and we're going to add that to 19. We're going to add that to 19, so 26 for Hazel Horse and then 19 for Pauly Pony. We want to add them because we're saying how many fence posts were used in all, or in Hazel's and Pauly's fences. Let's add these two together. First, let's go to the ones place. Six ones plus nine ones is 15 ones, but we only can write one digit here, so 15 ones is the same thing as five ones and one 10, right? 15 is just one 10 and five ones, so we've essentially regrouped those 10 ones as one 10 right over here, or as some people say, you carry the one, but that's all it's saying. We're saying six plus nine is 15. 15 is five ones and one 10. We wrote that one 10 in the tens place, and then one 10 plus two 10s plus one 10. Well, the one plus two plus one is four, so it's going to be four 10s, so 45. How many fence posts used in all? 45. Now, some of you all that might have somehow tried to maybe subtract the 19 from 26, that would have been what you would have done if they said, "How many more fence posts did the farmer use "for Hazel's fence than for Pauly's?" Then, you would subtract 19 from 26 to find the difference, but they didn't ask us how many more fence posts were used for Hazel than for Pauly, or how many fewer fence posts were used for Pauly than Hazel. They didn't ask us that. They said, "How many fence posts did the farmer use in all," and that's why we added.