ShmoopTube

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You probably have some friends who tend to exaggerate. [Two people walking down a school corridor]

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For example, they may overstate their height... Or maybe they claim to have the same vocal range as Ariana Grande [Guy singing badly on a stage]

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Before we move on check your ears and make sure they're not bleeding... [Guy pulls a Starburts out his ear]

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In normal life, this sort of exaggerating isn’t always welcome. [Kids sat on a bus]

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But in math, there’s always a totally acceptable way of making something seem a

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little more or a little less than it actually is. [Gorilla is driving the bus]

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We call it rounding.

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Rounding means to approximate a number by increasing or decreasing it slightly. [Coop pointing at the blackboard]

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So how does it work, well first we look at the number and find the place value we’re rounding to…

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Then we look at the number to the right.

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If that number is five or more, we round up. [Up arrow appears]

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If the number is four or less…

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… we round down. [Down arrow appears]

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You can use this cool mathmatical magic everywhere.

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You can round height, time, weight and so many other numbers.

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Probably not to your credit card bill though, don't push your luck. [Woman walking up to a bank desk]

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So how might this work in the real world.

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Well if you want a new video game that costs $67 dollars… [Poster for a video game]

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… and your mom say she’s not paying seventy dollars for a video game, she’s rounding up. [Kid looks annoyed]

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Of course, if the game goes on sale and now only costs $64…

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You can totally try to convince her to buy it by rounding down and saying it’s “only [Game sale poster at Christmas]

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sixty bucks.”

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You never know, it might work… [Mom says maybe Santa can afford it]

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Last thing: if you’re ever in doubt about which way to round – up or down – there’s

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a quick rhyme that’ll help you remember. [Teacher walks to the front of a class]

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It goes like this:

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“Five or more, raise the score; four or less, let it rest.”

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Catchy, right? Well, we liked it anyway... [Students look unimpressed]

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