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Estimate the length of an object to the nearest inch. Measure the length of an object to the nearest inch or centimeter.
Clarifications
Clarification 1: Instruction emphasizes measuring from the zero point of the ruler. The markings on the ruler indicate the unit of length by marking equal distances with no gaps or overlaps.Clarification 2: When estimating length, the expectation is to give a reasonable number of inches for the length of a given object.
General Information
Subject Area: Mathematics (B.E.S.T.)
Grade: 1
Strand: Measurement
Date Adopted or Revised: 08/20
Status: State Board Approved
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- NA
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
The purpose of this benchmark is for students to estimate length and formally and accurately measure the length of objects using a ruler. In Kindergarten, students used non-standard units such as paper clips to express the length of objects up to 20 units long (MTR.6.1).- Instruction includes getting students to understand that estimating is about making a reasonable guess. It is not about getting a “right” answer but thinking logically about estimating lengths when thinking about centimeters or inches (MTR.6.1).
- Instruction includes noting that there is a larger number of centimeters for an object than when that object is measured by inches because an inch unit is longer than a centimeter unit (MTR.5.1).
- Estimation of measurement focuses on inches as students may be more familiar with U.S. customary units, but instruction may also include centimeters (MTR.2.1).
Common Misconceptions or Errors
- Some students may not line the zero marking on the ruler to one of the ends of the item being measured. In these cases, students need to explore why lining up at the zero point gives the most accurate measurement and additional practice starting at 0 when measuring.
- Students may measure with the incorrect side of the ruler (i.e., using the centimeter side when needing to measure inches or using inches when needing to measure in centimeters).
Strategies to Support Tiered Instruction
- Instruction includes modeling how to measure an object and guiding students to notice that the objects measurement does not change if the object is placed further down the ruler.
- Modeling includes identifying the end points of an object and lining the end point with the zero mark of the ruler. Note that often the “zero” mark is not labeled and may be the end of the ruler or on the very first tick mark depending on the ruler. State the correct measurement and then as the student watches, move the object down the ruler and ask, “Does the object’s measurement change if its end point lines up with a different number?
- Instruction includes providing opportunities to make and use rulers so that students can construct their understanding of how lengths of each unit align to tick marks and numbers on a ruler.
- For example, students make and use their own ruler in 3 phases:
- Using paper square tiles glued to a strip of cardstock, students count the units that span an object to measure.
- Labeling each square tile with a number in the center of the unit, students use numbers to count the units of measure.
- Students draw tick marks at the end of each unit with a number starting at zero as shown, then eliminate the square tiles. Students use numbers to count the units.
Instructional Tasks
Instructional Task 1 (MTR.6.1)
Terri has a tiger plush toy that is 12 inches long. Her sister Kimberley has a smaller version of the same tiger plush toy. What would be a reasonable estimate for Kimberley’s tiger? How many inches could Kimberley’s tiger be if the difference between the two tigers is 4 inches?
Instructional Task 2 (MTR.7.1)
Theodore has a toy car that is 5 centimeters long. His best friend says that he has a toy truck that is 10 centimeters longer than Theodore’s toy car. If his best friend is correct, how long is the toy truck?
Instructional Items
Instructional Item 1
Provide students with several items to measure, such as a bouncy ball, paper clip, toy car or pencil. Use a table, like the one below to record answers from each part.
- Part A. Estimate the length for each item in inches.
- Part B. Use a ruler to measure the length of the item by inches or centimeters. Record the actual measurement in the space provided.
- Part C. Repeat until all items have been measured.
Instructional Item 2
If a reasonable estimate for the length of the broken eraser below is 1 inch, what would be a reasonable estimate in inches for the whole eraser shown?
Instructional Item 3
Kyle was measuring the length of his toy car. He stated his toy car was 4 inches long. Did Kyle measure the length of his toy car correctly? How do you know?
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.
Related Courses
This benchmark is part of these courses.
5012030: Grade One Mathematics (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 - 2024, 2024 and beyond (current))
7712020: Access Mathematics Grade 1 (Specifically in versions: 2014 - 2015, 2015 - 2018, 2018 - 2022, 2022 and beyond (current))
5012005: Foundational Skills in Mathematics K-2 (Specifically in versions: 2019 - 2022, 2022 - 2024, 2024 and beyond (current))
Related Access Points
Alternate version of this benchmark for students with significant cognitive disabilities.
MA.1.M.1.AP.1a: Use a ruler to measure the length of an object with exact whole units to the nearest inch.
MA.1.M.1.AP.1b: Explore familiar objects that can be used to develop a mental measurement benchmark to understand the relative size of an inch.
Related Resources
Vetted resources educators can use to teach the concepts and skills in this benchmark.
Formative Assessments
Lesson Plans
MFAS Formative Assessments
Measuring Michael’s Toy Car - 1:
Students are asked to explain a method for measuring length and to identify an appropriate tool.
Measuring Michael’s Toy Car - 2:
Students are asked to consider the zero point (origin) and end point when measuring the length of objects to the nearest inch.
What Do These Marks Mean?:
Students are asked to explain what the marks on a ruler represent and how to use a ruler to measure length.
Student Resources
Vetted resources students can use to learn the concepts and skills in this benchmark.
Parent Resources
Vetted resources caregivers can use to help students learn the concepts and skills in this benchmark.
