IXL | Estimate differences using compatible numbers up to 100

Use compatible numbers to estimate

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First, pick the better pair of compatible numbers.

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Now, use your choice to estimate the difference.

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is about

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Learn with an example

question

Use compatible numbers to estimate

–

First, pick the better pair of compatible numbers.

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Now, use your choice to estimate the difference.

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is about

key idea

Compatible numbers are good for estimating differences. They are close to the numbers you are given, and they are easy to subtract in your head.

solution

You want to estimate

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So, find compatible numbers that are close to 76 and 61.

75 is close to 76.

60 is close to 61.

75 and 60 are compatible numbers. They are easy to subtract in your head.

So,

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is a good way to estimate the difference.

Now, subtract the compatible numbers.

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So,

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is about

15.

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isn't as good of a way to estimate

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70 is too far from 76.

$Confetti$

Excellent!

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Teacher tools

Work it out

Not feeling ready yet? This can help:

P.4Subtract a multiple of 10 from a two-digit number

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