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100 Club: Add & Subtract Scale

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Hanna Ridgeway

Tier 1
For Schools

Lesson Plan

Proficiency Scale Lesson Plan

Students will learn to use a four-level proficiency scale describing criteria for adding and subtracting within 100, complete targeted practice problems, and self-assess their performance using the scale.

Understanding the proficiency criteria helps students know learning targets, fosters self-regulation, and builds a strong foundation in addition and subtraction within 100.

Audience

2nd Grade

Time

30 minutes

Approach

Review scale, model examples, guided practice, independent practice, self-assessment.

Materials

  • Proficiency Scale Poster, - Add & Subtract Within 100 Practice Worksheet, - Self-Assessment Chart, - Whiteboards and Dry-Erase Markers, and - Timer

Prep

Prepare Materials

10 minutes

  • Print and display the Proficiency Scale Poster.
  • Make copies of the Add & Subtract Within 100 Practice Worksheet for each student.
  • Print copies of the Self-Assessment Chart for each student.
  • Gather whiteboards, dry-erase markers, erasers, and a timer.

Step 1

Introduction to the Scale

5 minutes

  • Gather students and display the Proficiency Scale Poster.
  • Explain each level (1–4) with student-friendly language.
  • Provide examples of adding and subtracting problems that correspond to each level.

Step 2

Modeling and Discussion

5 minutes

  • Solve a sample problem (e.g., 47 + 36) on a whiteboard.
  • Identify which proficiency level the solution process meets and explain why.
  • Invite students to suggest what would move a level 2 solution to level 3.

Step 3

Guided Practice

8 minutes

  • Students work in pairs with whiteboards.
  • Teacher calls out problems from the Add & Subtract Within 100 Practice Worksheet.
  • Pairs solve and label their solution with a proficiency level.
  • Teacher circulates to check work and provide feedback.

Step 4

Independent Practice & Self-Assessment

7 minutes

  • Distribute the remaining practice problems from the Add & Subtract Within 100 Practice Worksheet.
  • Students solve problems independently.
  • After solving, students record their self-assessed level on the Self-Assessment Chart.
  • Encourage honest reflection and noting areas for improvement.

Step 5

Reflection and Closing

5 minutes

  • Invite volunteers to share a problem, their solution strategy, and self-assessed level.
  • Discuss strategies to advance to higher levels (e.g., mental math, checking work).
  • Remind students to reference the proficiency scale during future practice.
lenny

Slide Deck

100 Club: Adding & Subtracting Within 100

Tier 1 Math • 2nd Grade • 30 minutes

Welcome, everyone! Today we're going to learn how to use our proficiency scale for adding and subtracting within 100. We'll practice together, work in pairs, and then self-assess using our chart. Let's get started!

Learning Objectives

• Understand the four levels of the proficiency scale for addition and subtraction within 100
• Watch a modeled example and identify its level
• Practice problems with a partner and label your level
• Complete independent work and self-assess using the scale

Read each objective aloud. Emphasize that these are our goals for today.

Proficiency Scale Overview

Level 1: I need help and use drawings or counters
Level 2: I solve with steps on paper or with a number line
Level 3: I solve independently using written strategies
Level 4: I solve mentally and check my work

Display the Proficiency Scale Poster. Discuss each level with student-friendly language and examples.

Modeling & Discussion

Example: 47 + 36

  1. Add tens: 47 + 30 = 77
  2. Add ones: 77 + 6 = 83
    This uses steps on paper, so it’s Level 2/3. What would move it to a Level 3 or 4?

On your whiteboards, watch me solve 47 + 36. I’ll show my thinking and label the level. Then we’ll discuss why it fits that level.

Guided Practice

• Solve each problem together on your whiteboard
• Label your solution with Level 1, 2, 3, or 4
• Get feedback from your partner and me

Hand out whiteboards and markers. Call out problems from the Add & Subtract Within 100 Practice Worksheet. Students work in pairs to solve and label their level. Circulate and give feedback.

Independent Practice & Self-Assessment

• Complete remaining problems independently
• Record your self-assessed level next to each problem
• Think about what would help you reach the next level

Distribute the rest of the worksheet and the Self-Assessment Chart. Encourage honest reflection.

Reflection & Closing

• Who would like to share their strategy and level?
• How can you move from Level 2 to Level 3, or Level 3 to Level 4?
• Remember to use the scale during future practice!

Invite a few volunteers to share a problem, their strategy, and their self-assessed level. Highlight strategies that help move up a level.

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Activity

Adding & Subtracting Proficiency Scale Poster

Level 1: I need help and use drawings or counters

  • I’m learning how to add and subtract within 100.
  • I need drawings, counters, or my teacher’s help to solve problems.

Level 2: I solve with steps on paper or a number line

  • I write each step (e.g., add tens, then ones) or use a number line.
  • I break numbers apart to make the problem easier.

Level 3: I solve independently using written strategies

  • I choose and use my own strategy (e.g., place-value charts, decomposition).
  • I can explain my thinking clearly in words or pictures.

Level 4: I solve mentally and check my work

  • I add and subtract within 100 in my head.
  • I double-check my answer mentally without writing out all the steps.

—
Use this poster as a reminder of where you are in your learning. Set a goal to practice strategies that help you move up to the next level!

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Worksheet

Add & Subtract Within 100 Practice Worksheet

Instructions: Solve each problem within 100. Show your work below each problem and then write your self-assessed level (1–4) on the scale.

  1. 56 + 38 = _______ Self-Assessed Level: _______





  2. 73 − 29 = _______ Self-Assessed Level: _______





  3. 45 + 27 = _______ Self-Assessed Level: _______





  4. 90 − 14 = _______ Self-Assessed Level: _______





  5. 66 + 19 = _______ Self-Assessed Level: _______





  6. 82 − 47 = _______ Self-Assessed Level: _______





  7. 34 + 48 = _______ Self-Assessed Level: _______





  8. 59 − 33 = _______ Self-Assessed Level: _______





  9. 27 + 65 = _______ Self-Assessed Level: _______





  10. 100 − 58 = _______ Self-Assessed Level: _______





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Journal

Self-Assessment Chart

Use this chart to record your self-assessed level for each problem from the Add & Subtract Within 100 Practice Worksheet and reflect on your strategy.

  1. 56 + 38 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  2. 73 − 29 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  3. 45 + 27 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  4. 90 − 14 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  5. 66 + 19 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  6. 82 − 47 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  7. 34 + 48 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  8. 59 − 33 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  9. 27 + 65 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






  10. 100 − 58 = _______
    Self-Assessed Level (1-4): _______
    Reflection:






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