## Reflection: Checks for Understanding 3-Digit Perimeters - Section 2: Teaching the Lesson

I have included 2 video clips in this section to show a child who has an understanding of place value and can use it to expand the numbers and solve a problem, and a child who does not show as clear an understanding of place value.

I did not do as well as I should have in helping the second child to understand the process. You can hear me say "no no". I should have just been able to point out to the child the difference between writing just the digit in the hundred's place, and writing the whole number. I wanted him to take the time to write the whole number, but he was not grasping the difference. It took several steps to help the child slow down and write out the numbers so he could see that he was moving a group of ten into the tens place of the number.

This is such an important skill, to be able to take the number apart and put it back together again. I know that sometimes students want to rush ahead, but taking the time to build the foundation is so important to later math understanding.

Helping to explain the process
Checks for Understanding: Helping to explain the process

# 3-Digit Perimeters

Unit 13: Area, Perimeter and More Measurement
Lesson 5 of 6

## Big Idea: Students work with 3-digit numbers as they solidify their understanding of the difference between perimeter and area.

Print Lesson
Standards:
Subject(s):
Math, Place Value, Geometry, area (Measurement), expanded notation, perimeter, area, repeated addition, addition
60 minutes