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)
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?