CCSS.Math.Content.2.MD.A.4
The standard
Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.
Common Core State Standards for Mathematics · Measurement and Data
What this standard means
Students need to measure two objects with the same unit, then find the difference between their lengths. They should say both the amount and the unit, such as “The pencil is 3 inches longer than the crayon.” They need to use rulers or measuring tapes carefully, starting at zero.
Mastery looks like accurate measuring, comparing, and explaining the difference with a subtraction sentence or clear words. Students often get stuck when they line objects up at different starting points, start measuring at the ruler’s edge instead of zero, or answer with only “longer” without saying how much longer.
Ways to teach it
- Hands-on: Give pairs a ruler, pencil, crayon, marker, and glue stick, then have them measure each and record length differences in inches.
- Prompt: Show two measured objects and ask, “How do you know how much longer one is than the other?”
- Quick assessment: Hand students two classroom objects and ask them to measure, subtract, and write one comparison sentence with the unit.
- Real-world connection: Measure two students’ shoelaces or two book spines and decide how many inches longer one is.
Plan a lesson for CCSS.Math.Content.2.MD.A.4
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Related standards
- CCSS.Math.Content.2.MD.A.2
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...
- CCSS.Math.Content.1.MD.A.2
Express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that t...
- 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.