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Overview

A 3-day, 45-minute daily series designed to build Grade 2 students’ skills in using mental math addition strategies to solve two-digit addition problems flexibly and efficiently. This aligns tightly with the Common Core State Standards (CCSS), specifically:

CCSS.MATH.CONTENT.2.NBT.B.5
Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

This plan incorporates Georgia’s K-12 Mathematics Standards that mirror CCSS for Number and Operations in Base Ten for Grade 2.

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Day 1: Mental Math Foundations

Learning Goals

• I can use mental math strategies to add two-digit numbers.
• I can explain how I solve addition problems using doubling and making tens.

Success Criteria

• I use doubles facts (e.g., 24 + 24) to find sums quickly.
• I can make ten by breaking down numbers (e.g., 27 + 15 as 27 + 13 + 2).
• I explain my thinking clearly during a number talk.

Materials

• Base ten blocks (physical or visual)
• Whiteboards and markers
• Number talk prompts on cards: e.g., 24 + 26, 33 + 37, 18 + 22

Activities

1. Bell Ringer (5 minutes)

   • Show a quick problem on the board (e.g., 24 + 26). Ask students to solve mentally and share how they solved it.
   • Encourage multiple strategies and record diverse methods.

2. Number Talk (15 minutes)

   • Lead a discussion on doubling (24 + 24) and making tens (27 + 13 + 2).
   • Use base ten blocks visuals to support understanding.
   • Emphasize breaking numbers apart to create easier problems.

3. Guided Practice (15 minutes)

   • Students work in pairs with task cards to practice addition problems using doubling and making tens.
   • Circulate and prompt students to talk through their thinking.

4. Class Discussion & Reflection (5 minutes)

   • Students share their strategies and write one “I used doubling/making tens today” statement on their whiteboards.

5. Formative Assessment

   • Question: How did you use what you know about doubles or tens to solve your problem?
   • Use student explanations to gauge understanding and plan for differentiation.

Differentiation

• Support: Provide number lines and manipulatives for students who need concrete aids.
• Challenge: Ask advanced learners to find multiple ways to solve each problem and explain which is fastest and why.

Extension

• Create your own double addition problems and challenge a friend to solve them mentally.

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Day 2: Making Numbers Flexible

Learning Goals

• I can add two-digit numbers by making hundreds and tens.
• I can use place value understanding to solve addition problems mentally.

Success Criteria

• I use place value to regroup numbers when adding (e.g., 57 + 45).
• I break apart numbers to make 100 or tens before adding.
• I can show my work using base ten models or drawings.

Materials

• Base ten blocks or visuals
• Whiteboards and markers
• Task cards with problems like 57 + 45, 66 + 38

Activities

1. Quick Review (5 minutes)

   • Review doubling and making tens from Day 1 with a few oral problems.

2. Mini Lesson & Modeling (10 minutes)

   • Model adding with making hundreds strategy (e.g., 57 + 45 = 57 + 40 + 5; regroup 57 + 40 = 97; 97 + 5 = 102).
   • Use base ten blocks to visually represent these steps.
   • Emphasize flexible thinking and place value.

3. Independent Practice (20 minutes)

   • Students use whiteboards to solve task card problems.
   • Prompt them to picture base ten blocks or draw decomposed numbers to make hundreds/tens.

4. Partner Discussion (5 minutes)

   • In pairs, students explain their method and compare strategies.

5. Formative Assessment Questions

   • How did you break numbers apart to make adding easier?
   • Can you show me with drawings or base ten models?

Differentiation

• Support: Use step-by-step visual cues and scaffolded problems with smaller numbers for learners needing extra help.
• Challenge: Students create and solve their own problems making hundreds, then explain orally or through drawings.

Extension

• Challenge: Solve three two-digit numbers mentally using making hundreds strategy and explain your thinking.

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Day 3: Strategy Sharing and Application

Learning Goals

• I can choose and explain a mental addition strategy that works for me.
• I can solve two-digit addition problems using mental math flexibly.

Success Criteria

• I describe at least two mental addition strategies (doubling, making tens, making hundreds).
• I solve addition problems correctly using my chosen strategy.
• I reflect on which strategies I like to use and why.

Materials

• Student journals or reflection sheets
• Task cards with mixed addition problems
• Base ten blocks (optional)

Activities

1. Strategy Review Game (10 minutes)

   • Quick-paced game where you write problems on the board and students signal which strategy they will use to solve (doubling, making tens, making hundreds).
   • Discuss why.

2. Task Card Stations (20 minutes)

   • Rotate through 3 stations:
     1. Doubling problems
     2. Making tens problems
     3. Making hundreds problems
   • Students solve at each station using whiteboards and manipulatives as needed.

3. Reflection and Journaling (10 minutes)

   • Students write or dictate in journals:
     • Which strategy do I find easiest? Why?
     • Which strategy do I want to practice more?
   • Share a few aloud.

4. Formative Assessment

   • Observe and listen to the strategy choice explanations.
   • Ask: Which strategy helped you solve the problem the fastest? Which was easiest for you?

Differentiation

• Support: Allow use of drawings and base ten blocks for struggling learners.
• Challenge: Ask students to combine two strategies in one problem and explain their thinking.

Extension

• Create story problems that require two different addition strategies to solve; share with the class.

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Final Notes

• Classroom Environment: Foster a safe space where all strategies are valued, encouraging students to explain and reflect on their thinking without fear of mistakes.
• Use of Formative Checks: Regular questioning and observing pair discussions guide teacher’s next steps and personalized supports.
• Engagement: Incorporate movement (partner chats, stations) and multisensory materials (manipulatives, drawing) to support diverse learners.
• Assessment: Collect students’ reflections and whiteboard work as evidence of progress.

This plan offers a balanced mix of conceptual understanding, strategic thinking, and communication skills embedded deeply within the Common Core framework for Grade 2 mathematics.