How to Round to the Nearest 100,000 Using a Number Line | Lesson + Practice

Welcome to Math with Mr. J. In this video, I'm going to cover how to round to the nearest hundred thousand. And we're going to be using number lines to help us round. Number lines are going to give us a nice visual of rounding, and they'll help our overall understanding. We'll go through some examples together, and then I'll give you some practice problems that you can try on your own. Let's jump into number one, where we need to round 364,280 to the nearest hundred thousand. Now the first thing that we need to do here is find our end points. Since we are rounding to the nearest hundred thousand, we need to find the two multiples of 100,000 that our number is between. So 100,000, 200,000, 300,000, 400,000, and so on. Which 200,000 is 364,280 between? Well, we know this is between 300,000 and 400,000. 364,280 is greater than 300,000 and less than 400,000. So again, we can call these our end points. Let's mark them on our number line here. So 300,000 and 400,000. Our number is going to round to one of these end points. This will either round to 300,000 or 400,000. Now we need the midpoint, which is the halfway point between 300,000 and 400,000. That's going to be 350,000. So right here in the middle. That midpoint is important. It's going to help us round. Now let's plot our number on our number line. 364,280 is between 350,000, our midpoint, and 400,000. It's going to be right around here. So 364,280. Lastly, we need to round. So is our number closer to 300,000 or 400,000? Well, let's use our midpoint. Anything to the left of the midpoint rounds down to 300,000. Anything to the right of the midpoint rounds up to 400,000. And keep in mind, if a number is exactly at the midpoint, it also rounds up. Our number here is to the right of the midpoint. So 364,280 rounds to 400,000 when we round to the nearest 100,000. And by the way, that squiggly equal sign here, that is the approximate symbol. And we can use it when rounding. This tells us we have a number that's close, but not exact. These numbers are not equal. 364,280 isn't equal to 400,000. So we can't use an equal sign here. Instead, we use the approximate symbol to show that we rounded. Moving on to number two, we have 628,946. Let's round to the nearest 100,000. First, let's figure out our end points. Which 200,000 is our number between? Well, 600,000 and 700,000. Those are our end points here. So let's mark those. We have 600,000 and 700,000. Now we need our midpoint. That's going to be 650,000. 628,946 is greater than 600,000 and less than the midpoint of 650,000. It's going to be right around here. So 628,946. So which 100,000 are we closer to here? 600,000 or 700,000? Well, we're to the left of the midpoint and closer to 600,000. So 628,946 rounds to 600,000 when rounded to the nearest 100,000. Moving on to number three, we have 149,328. Let's round to the nearest 100,000. So what are our end points here? Which 200,000 is this between? Well, 100,000 and 200,000. So 100,000 and 200,000. Our midpoint here is 150,000. Now let's plot our number. 149,328 is close to our midpoint here, but slightly less. Slightly to the left. So right about here. So 149,328. Now again, this is close to the midpoint, but it's slightly to the left. That tells us our number is closer to 100,000. So 149,328 rounds to 100,000 when rounding to the nearest 100,000. Lastly, let's move on to number four, where we need to round 984,550 to the nearest 100,000. And this one is a little interesting. Let's start with the end points. Which 200,000 is this between? Well, our number is greater than 900,000. So that's our first end point. But what's our other end point? Think about counting up by 100,000. What comes next after 900,000? 1,000,000. So 1,000,000 is our other end point here. 1,000,000 is a multiple of 100,000. So this does work for one of our end points. Now our midpoint is 950,000. So let's mark that. And now we can plot our number. 984,550 is greater than that midpoint. It's right around here. So 984,550. So our number is to the right of the midpoint. And closer to 1,000,000. 984,550 rounds to 1,000,000 when rounded to the nearest 100,000. Now that we've gone through some examples together, it's time for you to try some practice problems on your own. So have paper and a pencil ready. So here are your practice problems. I'll give you five minutes and then we will go over the answers. Feel free to pause if you need more time or jump ahead to the answers whenever you are ready. Go ahead and start. Okay, so that was five minutes. Let's go over the answers. So here are our answers. Remember, we're rounding to the nearest 100,000 here. For number one, we should have 500,000. For number two, 800,000. For number three, 100,000. For number four, 900,000. For number five, 200,000. And then lastly, for number six, 900,000. Feel free to pause at this point if you need more time to check your work. So there you have it. There's how to round to the nearest 100,000 using number lines. I hope that helped. Thanks so much for watching. Until next time, peace.