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Current time:0:00Total duration:6:17

Rounding to nearest 10 and 100

CCSS.Math:

Video transcript

we've got four numbers here what I want to do is try to round each of these to the nearest 10 and to the nearest hundred so I encourage you to pause the video and try that right now so let's make two columns let's make one first for the nearest nearest ten and then make another column for the nearest 100 nearest 100 and let's start with 154 so 154 what is the multiple of 10 above 154 well it's 160 and the multiple of 10 below 154 is 150 so we're going to round up to 160 or down to 150 well when we rounding to the nearest 10 we need to look at the ones place one place to the right of the place that we're rounding so we look at this 4 in the ones place since 4 is less than 5 we round down to 150 now let's think about that same number rounding to the nearest hundred so 154 to the nearest hundred so now we need to think about if we were to round up what's the multiple of a hundred above 150 for 160 isn't a multiple of 100 the multiple of 100 above 154 is 200 what's the multiple of 100 below 154 well that's going to be 100 so if we're going to round to the nearest hundred so we look at the hundreds place we'll look one place to the right of that which is the tens place if that place is five or greater we round up if it's less than 5 we round down well this is clearly 5 or greater so we round up so this is interesting when we rounded to the nearest 10 since we had a 4 in the ones place we rounded down but when we rounded to the nearest hundreds since we had a 5 in the tens place we rounded up to 200 let's do some more of these this is fun so four thousand six hundred and seventy-four four thousand six hundred and seventy for the multiple of 10 above that is four thousand six hundred and eighty the multiple of 10 below that four thousand six hundred and seventy remember we're concerned only with the multiple of 10 so do we round up or down well we're thinking about rounding the tens place so it's see that's why it's either going to be an 8 if we round up or 7 if we round down to figure that out we look at the ones place the ones place is 5 or greater we round up if it's less than 5 we round down it's once again less than 5 so we round down to 4670 now let's round the same number to the nearest hundred four thousand six hundred and seventy four what's the multiple of 100 below this well the multiple 100 below this is four thousand six hundred the multiple of 100 above this is four thousand seven hundred if we're trying to think about rounding to the nearest hundred we want to look at the tens place the tens place is five or greater so we round up to four thousand seven hundred now let's tackle nine thousand nine hundred and ninety five and once again always try to pause these if you haven't done so already to try to do this on your own so nine thousand nine hundred and ninety five what is the multiple of 10 below this well the multiple ten below this is nine thousand nine hundred and ninety and what's the multiple of 10 above this well if you increase this by ten you actually get to ten thousand you get to ten thousand so you might say hey well isn't this a multiple of 100 and actually this is a multiple of a thousand it's also a multiple of ten thousand it's all of those but the multiple of ten right above nine thousand nine hundred ninety five is ten thousand you just have to add a little bit to this to get to ten thousand or the multiple of 10 below it is clearly nine thousand nine hundred ninety 10 more than that gets you to ten thousand so how do we round this well once again if we're rounding to the nearest ten we want to look at the ones place the ones place is five or greater so we round up to ten thousand now let's round to the nearest hundreds we should be getting used to this now to the nearest hundreds what is the hundreds below this well it's nine thousand nine hundred nine thousand nine hundred what is a hundred above this and next multiple of 100 above this well if you add 100 to 9900 you once again get 10,000 so how do we decide whether to round up or down well we don't look at the ones place anymore we're now rounding to the nearest hundred so we want to round to the nearest hundred to do that we look one place to the right which is the tens place if this is five or greater we round up if it's less than 5 we round down it is 5 or greater so once again we round up to 10,000 now we have one more eight thousand three hundred and forty six so eight thousand eight thousand three hundred and forty six the tens place or that the multiple of 10 below it is eight thousand three hundred and forty multiple of 10 above that is eight thousand three hundred and fifty if we're going to round to the nearest ten we need to look at the ones place the ones place is five or greater so we round up now let's round to the nearest hundred eight thousand three hundred and forty six the hundreds multiple of 100 above this is eight thousand four hundred the multiple of 100 below this is eight thousand three hundred notice we're rounding to the nearest hundreds if we were to round up the hundreds place becomes a four if we round down the hundreds place stays of three but it's followed by zeros if we want to round to the nearest hundreds we need to look at the tens place the tens place here is less than 5 so we round down to eight thousand three hundred notice again when we rounded to the nearest tens we rounded up to eight thousand three hundred fifty when we round to the nearest hundreds we rounded down to eight thousand three hundred