Use place value understanding to round decimals to any place.

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Students are able to… 

  • Use their understanding of place value to round decimal numbers to a given place on a number line model.
  • Determine which number a decimal lies between using a number line.
  • Share clear explanations to justify their thinking beyond using a rule.

Students are able to…because teachers:

  • Provide real-world contexts for students to use in rounding decimals to the appropriate place.
  • Connect previous experiences with rounding whole numbers using the number line to rounding decimals using a number line.
  • Model using benchmark numbers to determine where to place a decimal on a number line.

For example:

  • 73 is greater than 9.7 and less than 9.8
  • 75 is halfway between 9.7 and 9.8
  • 73 is less than 9.75 so it falls between 9.7 and 9.75.

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Questions to ask students:

  • What are the two benchmark decimal numbers that 12.62 lies between on a number line?
    • Sample answer that indicates understanding:
    • Sample answer that indicates an incomplete understanding or a misconception:
  • Ray finished a race in 13.48 minutes. What was Ray’s finishing time to the nearest tenth?
    • Sample answer that indicates understanding: In the decimal number 13.48, there are 13 ones (or minutes), 4 tenths, and 8 hundredths. 48 lies between 13.4 and 13.5 on the number line and it is closer to 13.5 so 13.48 will round to 13.5.
    • Sample answer that indicates an incomplete understanding or a misconception: 48 rounds up because 8 is five or more so it rounds to 13.58.
  • List 4 numbers that round to 2.6 when rounded to the nearest tenth.
    • Sample answer that indicates understanding: 2.59, 2.62, 2.64, 2.56
    • Sample answer that indicates an incomplete understanding or a misconception: 2.6 rounds to 3. (misconception that all numbers round to a whole number)

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FSA Notes

Cognitive Complexity Level: Level 1: Basic Recall

Achievement Level Descriptors:

Level 2: uses place value understanding of decimals to round to the nearest whole number

Level 3: uses place value understanding to round multi-digit numbers between millions and thousands place to any place

Level 4:uses rounding strategies in real-world situations

Level 5: determines a number that falls between two numbers of different place values

Assessment Limits: 

Items may contain decimals to the thousandths with the greatest place value to the millions.

The least place value a decimal may be rounded to is the hundredths place.

Context: Allowable

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Additional Resources:

Additional in depth content knowledge:

http://www.katm.org/flipbooks/5%20FlipBook%20Final%20CCSS%202014.pdf#page=27

 

Video: Rounding to the nearest tenth:

https://learnzillion.com/lesson_plans/6848-round-decimals-to-the-nearest-tenth

Video: Rounding to the nearest hundredth:

https://learnzillion.com/lesson_plans/7226-round-decimals-to-the-nearest-hundredth

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Sample Formative Assessment Tasks: (Click to enlarge the task image)

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Resources/Tasks to Support Your Child at Home:

  • Online game for your child to practice rounding to the nearest tenth, hundredth, or thousandth

https://www.turtlediary.com/game/rounding-decimals-up-to-thousandths.html

  • Real-World Situation: Tim went to the grocery story and saw apples were $1.69/pound. If the total weight of his bag of apples was 3.289 pounds, would he be closer to paying for 3.2 pounds or 3.3 pounds?