# Lesson 3 Create and Use a Ruler

Let’s create rulers and use them to measure and compare lengths in centimeters.

## Warm-up Number Talk: Subtract Two Digits

Find the value of each expression mentally.

## Activity 1 Create a Ruler

Use your tools to make a ruler that shows lengths in centimeters.

Compare your ruler with your partner’s ruler.

## Activity 2 Measure and Compare Lengths

## Problem 1

Use your ruler to measure the length of each rectangle. Don’t forget to label your measurements.

## Problem 2

How many centimeters longer is rectangle a than rectangle b?

## Problem 3

How many centimeters longer is rectangle f than rectangle d?

## Problem 4

Which two rectangles are the longest? How long would the rectangle be if you joined them together?

## Practice Problem

## Problem 1

How many centimeters long is each side of the triangle? Label each side.