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TouchMath Extend

Lesson 51: Inches and Centimeters

Lesson Objectives

  • Learn unit names and abbreviations within both the standard and metric systems 
  • Demonstrate measurement of length by reading increments with customary (standard) units to the inch and metric units to the centimeter 
  • Demonstrate measuring length by placing tools end to end with no gaps or overlaps 
  • Measure objects found in everyday activities 
  • Select the appropriate tool to measure an object 
  • Select objects that would most likely be measured with a given tool 
  • Select a tool and measure the lengths of given items  
  • Measure an object to the nearest given unit and then to mixed units (e.g., feet and inches) 
  • Demonstrate basic application of measurement in both systems in everyday activities 


  • Extend Workbook (Page 51) 
  • Rulers, yardstick, tape measure 
  • Standard-length paper clips and smaller paper clips 
  • Items to measure: e.g., string, yarn, straws, shredded pieces of paper 

Step 1: Warm Up (5 min)

Take out different length items (e.g. different pieces of string, yarn, shredded pieces of paper), and place them next to each other or hanging from the white board for students to see. Explain that each item is a certain length and we can measure using rulers, yardsticks, and tape measures (take out each and show). Based on how long something is will determine what you use to measure. Measure each item using a ruler and write the measurement below. 

Step 2: Vocab Review (5 min)

Introduce new vocabulary: inches (in), centimeters (cm), length, and long. When teaching inches and centimeter, take out a ruler to visually show the difference. Use actual items to show how many inches or centimeters it is. Explain length is another word for how long something is. To teach what “how long” means, pull out two items and say one is longer or shorter than the other (two pencils, two different size paper clips). Explain that America and a few other countries use the Imperial System for measurement (inches, feet, yards, and miles to measure distance or length), while the rest of the world uses the Metric System: millimeters, centimeters, meters, and kilometers. 

Step 3: Model (5 min)

After teaching new vocabulary and visually showing different forms of measurements, make separate lists of items that you could probably use a ruler to measure, a yard stick to measure, and a tape measure (e.g. book, whiteboard, pencil, bed, pillow, television, fork, cell phone, etc.). Review parts of the ruler and how many inches are in a foot, how many cm on a ruler (30cm) and demonstrate measuring items using inches and cm. Use the yardstick and tape meausure next to demonstrate measuring larger items. 

Step 4: Guided Practice (5 min)

Give students rulers and items to measure and review the parts of the ruler, including the tick marks. Explain the tick marks are different lengths: the longest tick marks are where the inches are and the smaller tick marks represent half inches. They can be broken down further but we are just focusing on whole numbers today. On the centimeter side, the smaller tick marks represent milimeters. In pairs, have students measure items, both agreeing to the starting and ending measuring points. Log measurements on a piece of paper, measuring in both inches and centimeters. 

Step 5: Student Practice (5 min)

Go to Student Workbook Page (51). Read the directions. Write the lenths of the given items on the lines provided, paying attention to the endpoint of the measurement. Say the answer aloud, including the unit of measure (inches or centimeters). 

Step 6: Wrap Up (5 min)

To wrap up the lesson, review the learning objectives and core vocabulary words again and ask your students about their experience.