Lesson 10

Midamos con una cinta rota

Lesson Purpose

The purpose of this lesson is for students to measure objects without lining up the end with the 0 mark.

Lesson Narrative

In earlier lessons, students used rulers, measuring tapes, yardsticks, and meter sticks to measure lengths in inches, feet, centimeters, and meters. They learned that length units are represented on these tools as the length between tick marks. They learned that if they line up the edge of an object with zero on their tools, they can easily read the measurement from the tool without counting each length unit.

In this lesson, students extend their experiences with measurement to include situations when they can not use a tool to measure from 0. They know from prior experience that simply moving an object in space does not change its length (conservation of length). However, this understanding is challenged when students see an object that is not lined up with 0 on a measuring tool. Throughout the lesson, students are encouraged to make sense of and use equations that represent the measuring problems in each task (MP2). This understanding will support learning in future units with representing addition and subtraction on the number line.

  • Action and Expression
  • MLR2

Learning Goals

Teacher Facing

  • Determine the measurement of an object with a measuring tool when the endpoint does not line up with 0.

Student Facing

  • Midamos sin empezar en el 0.

Required Materials

Required Preparation

Activity 1:

  • Each group of 2 needs access to several objects between 2–10 inches long. Consider using classroom objects such as markers, colored pencils, paperclips, or other objects or images used in previous activities.

CCSS Standards

Building On


Building Towards

Lesson Timeline

Warm-up 10 min
Activity 1 15 min
Activity 2 20 min
Lesson Synthesis 10 min
Cool-down 5 min

Teacher Reflection Questions

What connections did students make between the different methods shared? What questions did you ask to help make the connections more visible?

Suggested Centers

  • Capture Squares (1–3), Stage 4: Subtract within 20 (Supporting)
  • Math Stories (K–2), Stage 5: Tape Diagrams (Supporting)

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Student Task Statements pdf docx
Lesson Cover Page pdf docx
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Teacher Presentation Materials pdf docx