What's the Difference?

  • Second Grade
  • Math
  • 40 minutes
  • Standards: 2.OA.B.2
  • no ratings yet
October 13, 2015
by Yolanda Swain

Give your students a great basis in mathematics with this lesson that has them use a number line to find differences for basic subtraction facts.

Learning Objectives

Students will be able to count back to find the difference.

Download Lesson Plan

Lesson

Introduction (5 minutes)

  • Write large numbers 1 through 10 on construction paper and give 10 students one number to hold in front of the class.
  • Write the subtraction sentence "7 - 5" on the board.
  • Ask the student who is holding the number 7 to hold it up high.
  • Then ask students which direction should we go to subtract 5.
  • Once students agree to count back, ask the child holding the number 6 to step forward.
  • Next ask the student holding the number 5 to step forward. Continue these steps until 5 students have stepped forward.
  • Write "2" to complete the subtraction sentence "7 - 5= 2."
  • Tell students that today they're going to learn about counting back to find the difference.

Explicit Instruction/Teacher Modeling (5 minutes)

  • Read aloud the following word problem: "Josh has 9 pencils. He gives 4 pencils away. How many pencils does Josh have left?"
  • Introduce the number line to model the word problem.
  • Show how to start at the first number, 9, and count back by the second number, 4.
  • Repeat the activity for 8 - 3 = 5 and 6 - 4 = 2.
  • Tell students that the number you end on is the difference.

Guided Practice/Interactive Modeling (10 minutes)

  • Cut the number line sheet into strips.
  • Distribute a number line and a copy of the Subtraction worksheet for each child.
  • Help students work through the first problem.
  • Have students put a finger on the first number and count back moving each step on the number line.
  • Work through the first three problems as a class.

Independent Working Time (10 minutes)

  • Have students work through the exercises on the worksheet independently.

Extend

Differentiation

  • Enrichment: For advanced students, let them complete the exercises independently without the number line.
  • Support: For students who need support, help them to use the number line in a small group or one on one setting.

Review

Assessment (5 minutes)

  • Observe students as they use the number line or any other strategy to subtract basic facts.

Review and Closing (5 minutes)

  • Ask students to explain how you find the difference for 11 - 6.

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