Lesson

## 1st Grade Math - Developing Student Understanding of Non-Standard and Standard Measurement

# Clip 4/17: Measurement Lesson Part A3

## Overview

Tracy Sola contrasts two different student responses to the turn-and-talk: “Monica said that Ariana has the biggest feet because she has 12. And then Salvador said, “No, she has the smallest.” So, now we have two different opinions. Monica thinks she has the biggest feet because she has the biggest number. And why do you think she has the smallest feet, Salvador?”

Another student notes that there might have been differences in the children’s approaches to the measurement challenge, such as “leaving gaps” between their feet as they counted. Sola shares the idea of accuracy; that “That word means that you're very careful … when we measure, we will be very careful to measure carefully and not leave gaps, so we know what it really is.”

When the students were walking across the tape and seeing how many footsteps it would take to get to the end of the tape, most of the students were very careful to go heel to toe, heel to toe. There was one student who was walking with some big gaps, and right away the other kids jumped in and said, "You have gaps. You have gaps." And so, they were thinking about that naturally, without me saying anything about it or anybody mentioning it, and that just seemed very natural for them.

There were some people who didn’t understand that gaps created problems, so it took a little bit of pure discussion and group discussion to get to that idea. So, that was really interesting. You could see the wheels turning and you could see them thinking about that apparent contradiction and why that would be.