Unit 4 Contents

Rhonda and Joe solved Question 13 differently.

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1. Look at their solutions. Which strategy could you do in your head or with a few notes?
2. Which strategy do you like better?

Using Base-Ten Pieces to Estimate

Grace has 325 baseball cards. Her sister Rosie has 416. Rosie said, “Together we have more than 1000 baseball cards!”

Grace disagreed. She said, “I think we only have a little more than 700 baseball cards all together.”

Which girl has the more reasonable estimate?

Thinking about base-ten pieces is one good way to estimate. Grace has 3 flats and some skinnies and bits. Rosie has 4 flats and some skinnies and bits. That's 7 flats, and some more.

15. Ming has a collection of 225 stickers and Shannon has a collection of 247 stickers.
    Ming and Shannon combined their collections.
    Ming said, “Together we have more than 500 stickers.”
    Shannon said, “Together we have less than 500 stickers.”
    Who has the more reasonable estimate? Tell how you know.