Show case of a Math Lesson

Instructional Goals

Through this activity, Grade 5 students will develop an understanding that when we measure, the point of origin begins at zero, which we call the zero point.
Grade 5 students will also understand that the starting point is flexible and can be shifted to measure. This entails understanding that linear measure is a measure of distance travelled.

Description of the Task

We asked Grade 5 students if we can measure our line if our ruler is broken, and how? Once the students finished writing their solutions they shared their ideas, compared and contrasted them. Then, students were asked if they could measure a line longer than the broken ruler. After the students developed ideas, we compared them until reaching a final solution. We concluded the lesson by going over key findings and understandings developed in the lesson.

Image of the Task:

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Analysis of Student Thinking:

Student A

Looking at this students’ work, we can see that they agree that we can use the broken ruler to measure the short line. As shown above the student explains in writing that because the line is smaller than the ruler, we can measure the line which according to this student is 1 cm. However, the student argues that we cannot measure the longer line as the ruler is not long enough. To target the content goals of the lesson, it was important to recognize this response first to allow all students thinking to be represented in the discussion while investigating mathematical ideas.

Student B

This student similarly agrees that we can measure the short line with the ruler. This student also agrees that we can measure the longer line with the same ruler. Based on this student's written explanation and drawing we were able to introduce and discuss one of the targeted goals which is that the starting point is flexible when measuring. From the students' drawings we were also able to introduce terms such as iteration, an important term surrounding the idea of measurement that is important in developing mathematical communication.

It was with this student's written explanation and drawing that we were able to introduce and discuss the term iteration, an important term surrounding the idea of measurement.