Lesson Plan

Mistakes in Comparing Multi-Digit Numbers

In math, mistakes are welcome! This lesson helps your students identify and fix errors made while comparing three- to four-digit numbers. Teach the lesson on its own or as support to the lesson Let's Compare Whole Numbers!
This lesson can be used as a pre-lesson for the Let's Compare Whole Numbers lesson plan.
View aligned standards
This lesson can be used as a pre-lesson for the Let's Compare Whole Numbers lesson plan.



Students will be able to compare two multi-digit numbers.


Students will be able to correct and explain errors in multi-digit number comparisons, using key grade level vocabulary, with the support of sentence starters.


(3 minutes)
Errors in Comparing NumbersVocabulary Cards: Mistakes in Comparing Multi-Digit NumbersGlossary: Mistakes in Comparing Multi-Digit NumbersTeach Background Knowledge TemplateWrite Student-Facing Language Objectives Reference
  • Ask students to consider the word compare. State an example of a time you compared two things (e.g., "I wanted to buy a new soccer ball for my son so I compared the two kinds they had in the store. One was bigger than the other. It was red. The smaller one was blue. I decided to get the smaller one because it was a better size for my son. It was also cheaper than the red one.").
  • Have them turn to a partner and talk about words, pictures, or sentences they think of when they think of comparing. State the following questions to get students interested in the concept of comparing: What does it mean to compare things? When in your life have you compared? Invite students to share key points from their conversation with their partner and jot down their remarks.
  • Explain that comparisons happen all the time. We compare food, toys, books, movies, people, places, and more on a daily basis without even realizing it. Tell students that today they are going to practice comparing whole numbers with up to four digits. Specifically, they will look at errors or mistakes that others have made while comparing numbers, discuss the mistake, and fix it.