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https://www.khanacademy.org/math/grade-4-math-tx/x5ff7ebd8e2c0fc69:addition-and-subtraction-of-whole-numbers-and-decimals/x5ff7ebd8e2c0fc69:estimate-sums-and-differences/v/estimating-large-sums

Let's estimate sums by rounding numbers to the nearest ten, hundred, or thousand to make adding easier. Estimating helps us check our answers and solve problems quickly in real life—like when shopping or planning a party. Get ready for some fun math tricks!

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