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Lesson Plan

10. Mystery Number: Using understanding of place value to round decimals in word problems (A)

teaches Common Core State Standards CCSS.Math.Content.5.NBT.A.4
teaches Common Core State Standards CCSS.Math.Practice.MP6
teaches Common Core State Standards CCSS.Math.Practice.MP7
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Lesson objective: Apply understanding of rounding decimals to any place value.

This lesson provides an opportunity for students to apply their knowledge and understanding of rounding decimals to a mathematical situation. Students are asked to determine a mystery number by applying the given parameters to their understanding of place value and the rounding of decimals.

Key Concept students will use: 

  • Decimals can be rounded just as whole numbers can.

Skills students will use:

  • Understanding of place value
  • Rounding whole numbers to the nearest 10 or 100 (Grade 3, Unit 3)

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they round decimals to any place using number lines, place value charts, and their understanding of place value.  

Key vocabulary: 

  • decimal
  • hundredths
  • number line
  • place value
  • rounding
  • tenths
  • thousandths

Special materials needed:

  • scratch paper, as needed
Related content

Appears in

Comparing and rounding decimals

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