Lesson Plan

Objectives

This lesson encourages children to explore and to develop a broader understanding of subtraction and the relationship of addition and subtraction. Students will:

  • use addition and subtraction strategies.
  • write equations/number sentences to represent their thinking.
  • explore different operations to strategize and reach the goal number.

Essential Questions

How are relationships represented mathematically?
How can expressions, equations, and inequalities be used to quantify, solve, model, and/or analyze mathematical situations?
How can mathematics support effective communication?
How can patterns be used to describe relationships in mathematical situations?
How can recognizing repetition or regularity assist in solving problems more efficiently?
How is mathematics used to quantify, compare, represent, and model numbers?
  • How can expressions, equations, and inequalities be used to quantify, solve, model, and/or analyze mathematical situations?
  • How are relationships represented mathematically?

Vocabulary

  • Subtraction: To take one quantity away from another.

Duration

50 minutes

Prerequisite Skills

Prerequisite Skills haven't been entered into the lesson plan.

Materials

Related Unit and Lesson Plans

Related Materials & Resources

The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.

Formative Assessment

  • View
    • Observations during work time will assist in determining the strategies students have mastered and the strategies for which students require more support.
    • Think-Pair-Share: at the end of the lesson have students share their strategies and points scored during the activity.

Suggested Instructional Supports

  • View
    Scaffolding, Active Engagement, Modeling, Explicit Instruction
    W: Introduce the twenty-frames as an option to help students with their thinking.  
    H: Ask students to use the numbers 4, 5, 3, and 0 to try to reach their goal number of 7. Once they explore different ways, let them know that now you would like them to try reaching the goal of 7 by using as many of the four numbers given as possible.  
    E: Give one deck of cards to each group of four or five students. Ask them to draw four cards and then draw a fifth card, which will be their goal number.  
    R: Have students explain strategies and operations they could use to reach the goal number. Remind them they should use as many cards as possible because the cards are their points. They will record the equation for their strategy on the recording sheet.  
    E: In pairs, have students share their work and explain how they reached their goal numbers. 
    T: Modify the numbers by giving students cards 0–10, 0–50, or 0–100.  
    O: This lesson introduces using addition and subtraction in the same equations. 

Instructional Procedures

  • View

    “We have been using ten-frames and number lines as tools to help us with addition and subtraction problems. Today we are going to use what we know about addition and subtraction to play a game called Goal Number.”

    Display a twenty-frame (M-1-3-3_Twenty-Frames.doc). Take a few minutes to let students make observations about how the numbers are organized if they have not used a twenty-frame recently. They should notice that a twenty-frame is made from two ten-frames. They should see the darker lines which represent a 10 or a 5.

    “What do you notice about this twenty-frame tool?”

    If students don’t notice what you are looking for, use prompting questions such as: “How many squares are on the top row? How many are to the left of the line? How many are on the right?”

    Ask students, “If you had 4 chips on the twenty-frame, how many more would you need to make 11?” Model what they talk about on the twenty-frame.

    Explain to the class that today they are going to practice reaching a goal number. “If you had the numbers 4, 3, 5, and 0; which numbers would you use to reach a goal number of 7?”

    Have students talk with their groups of four or five about what strategies they might use to reach the goal number.

    “Talk with your group about what strategy will work best if the goal is to use the most numbers/cards possible?” (Possible strategies: Use the smallest numbers first, combine addition and subtraction, etc.)

    After a few minutes ask groups to share their strategies. Record them on a larger version of the recording sheet (M-1-3-3_Goal Number Recording Sheet.doc).

    “Today in pairs you will play several rounds of the Goal Number game. You will record your final equation for the strategies you choose and the points you earn.”

    Have one partner get the numeral cards (M-1-3-3_Numeral Cards.doc) and the other partner the recording sheet (M-1-3-3_Goal Number Recording Sheet.doc) and find a spot to play. Allow enough time for students to play several rounds or to allow you enough time to talk with each partner pair at least once.

    When the time is up, gather the students and have them share their total number of points for the rounds they played. Discuss strategies children used to get the most points. Also discuss which numbers were the hardest to reach and why they think that was the case.

    Optional: Create a class poster of “high points” for the game.

    Extension:

    • Expansion: Change the numbers for Goal Numbers to meet the needs of your students. Have numeral cards up to 50 or 100 for advanced learners.
    • Workstation or Small Group: Provide number lines for students who have difficulty with twenty-frames or mental strategies (M-1-3-2_Number Line.doc). Have students circle the goal number on the number line, then experiment with the numeral cards to see how to best reach that goal number.

Related Instructional Videos

Note: Video playback may not work on all devices.
Instructional videos haven't been assigned to the lesson plan.
Final 3/14/14
Loading
Please wait...