CCSS.Math.Content.2.MD.A.2
The standard
Measure the length of an object twice, using length units of different lengths for the two measurements; describe how the two measurements relate to the size of the unit chosen.
Common Core State Standards for Mathematics · Measurement and Data
What this standard means
Students need to measure the same object two times with two different unit lengths, such as inches and feet, or centimeters and meters. They should see that smaller units give a bigger number, and larger units give a smaller number.
Mastery looks like a student measuring carefully, recording both numbers, and explaining the relationship in words. Common trouble spots are lining up the ruler at zero, leaving gaps or overlaps with unit tools, and thinking the larger number means the object is longer.
Ways to teach it
- Have students measure a desk with inch tiles, then with foot strips, and record both results on a two-column chart.
- Ask, “Why did the desk measure more inches than feet if the desk did not change?” and have students write two sentences.
- Show a pencil measured in centimeters and inches, then ask students which unit gives the larger number and why.
- Measure a classroom rug with paper feet and yardsticks, then connect it to why stores sell carpet by larger units.
Plan a lesson for CCSS.Math.Content.2.MD.A.2
Generate a complete lesson plan aligned to this standard, with objectives, activities, and materials. Free, no account needed.
Related standards
- CCSS.Math.Content.2.MD.A.4
Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.
- CCSS.Math.Content.1.MD.A
Measure lengths indirectly and by iterating length units.
- CCSS.Math.Content.2.MD.A
Measure and estimate lengths in standard units.
- CCSS.Math.Content.2.MD.A.1
Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.