Broken Rulers

Broken Rulers

By Erika Larson

What is a broken ruler?

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How can you do this?

Method 1:

Subtract

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Method 2: Count on​

Fill in the Blanks

Subtract:

21 - 18 = 3 inches

​Count on:

18-19, 19-20, 20-21 = 3 inches!​

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Fill in the Blanks

Did you get 2 inches?

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Let's try another..​

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Fill in the Blanks

I counted up using my fingers like this...

Start with 4, tap for each number

5, 6, 7, 8, 9

5 inches!​​

Fill in the Blanks

I subtracted this time, like this:

12 - 8 = 4

4 inches!

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​- Name of Author

Great job !!

Go back to Formative to practice more​