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Math Fact Masters

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Rubric

2.OA.2.1 Fact Fluency Rubric

Standard: Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.

LevelDescription
4 - ExpertConsistently and independently adds and subtracts within 20 with speed and accuracy. Demonstrates immediate recall of all sums of two one-digit numbers and flexibly applies multiple mental strategies without prompting. May explain strategies clearly to others.
3 - ProficientFluently adds and subtracts within 20 using appropriate mental strategies. Recalls most sums of two one-digit numbers from memory. Shows accuracy and reasonable speed when solving problems.
2 - DevelopingAttempts to use mental strategies for addition and subtraction within 20, but may require occasional prompting or make errors. Recalls some sums of two one-digit numbers, but often relies on counting strategies (e.g., fingers, number line) for others.
1 - NoviceHas difficulty adding and subtracting within 20, even with support. Primarily relies on concrete manipulatives or counting for most problems. Shows limited recall of sums of two one-digit numbers.
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Lesson Plan

Math Fact Masters

Students will fluently add and subtract within 20 using mental strategies and recall from memory all sums of two one-digit numbers.

Mastering basic addition and subtraction facts is crucial for all future math learning. It builds confidence and makes more complex problems easier to solve.

Audience

2nd Grade

Time

30 minutes

Approach

Through a warm-up, direct instruction, guided practice, and independent practice.

Materials

Warm-Up: Mental Math Challenge, Slide Deck: Math Fact Mastery Slides, Worksheet: Fact Fluency Practice, Answer Key: Fact Fluency Answer Key, Cool-Down: Exit Ticket: How Do You Know?, Rubric: Math Fact Fluency Rubric, Quiz: Math Fact Masters Quiz, and Answer Key: Math Fact Masters Quiz Answer Key

Prep

Teacher Preparation

10 minutes

Step 1

Warm-Up: Mental Math Challenge

5 minutes

  1. Display the Mental Math Challenge on the board.
  2. Instruct students to solve the problems mentally and write down their answers.
  3. Quickly review answers as a class, asking students to share their mental strategies.

Step 2

Introduction to Strategies (Slides)

7 minutes

  1. Present the Math Fact Mastery Slides, focusing on slides that introduce or review mental strategies for addition and subtraction within 20 (e.g., making ten, doubles, near doubles, counting on/back).
  2. Use the script in the slides' teacher notes to guide the discussion and provide examples.

Step 3

Guided Practice: Whiteboard Wonders

8 minutes

  1. Provide each student with a whiteboard and marker.
  2. Project various addition and subtraction problems within 20 from the Math Fact Mastery Slides (or create new ones).
  3. Instruct students to solve each problem on their whiteboard, using a mental strategy.
  4. After each problem, have students show their answers. Discuss different strategies used by students.

Step 4

Independent Practice: Fact Fluency Worksheet

7 minutes

  1. Distribute the Fact Fluency Practice worksheet to each student.
  2. Instruct students to complete the worksheet independently, focusing on using the mental strategies discussed.
  3. Circulate to provide support and assess student understanding. Collect the worksheets for later assessment using the Fact Fluency Answer Key and Math Fact Fluency Rubric.

Step 5

Cool-Down: Exit Ticket

3 minutes

  1. Distribute the Exit Ticket: How Do You Know?.
  2. Instruct students to answer the prompt, reflecting on a strategy they used.
  3. Collect exit tickets to gauge individual understanding and inform future instruction.
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Slide Deck

Unlock Your Inner Math Fact Master!

Do you want to solve math problems super fast?
We're going to learn some awesome tricks to become Addition and Subtraction Experts!

Welcome students and introduce the idea that math can be fun and easy when we use smart strategies. Explain that today, we'll become 'Math Fact Masters' by learning cool tricks to solve addition and subtraction problems quickly in our heads!

Mental Math Challenge!

Solve these in your head!

  1. 5 + 3 = ?
  2. 10 - 4 = ?
  3. 7 + 7 = ?
  4. 12 - 5 = ?

Display the warm-up challenge. Give students 1-2 minutes to solve these in their heads or on a small whiteboard. Remind them to think about how they are solving them. After, quickly review the answers, asking a few students to share their 'mental strategies' even if they haven't explicitly learned them yet.

What are Mental Strategies?

They are clever tricks your brain uses to solve math problems quickly!

  • No fingers needed!
  • Makes math easier and faster!
  • Helps you become a math wizard!

Introduce the concept of 'mental strategies.' Explain that these are like secret shortcuts our brains can use to solve problems without needing to count on fingers every time.

Strategy 1: Make a Ten!

It's easy to add to 10!

Example: 8 + 5

Think: 8 needs 2 more to make 10.
Take 2 from 5 (5 is 2 + 3).
So, 8 + 5 becomes (8 + 2) + 3 = 10 + 3 = 13!

Introduce the 'Make Ten' strategy. Explain that our brains love the number 10. Give an example like 8 + 5. Show how 8 needs 2 to become 10, and if we take 2 from 5, we are left with 3. So, 8+5 becomes 10+3=13.

Strategy 2: Doubles & Near Doubles

You know your doubles!

Example: 6 + 6 = 12

Near Doubles: 6 + 7

Think: 6 + 7 is just like (6 + 6) + 1!
So, 12 + 1 = 13!

Introduce 'Doubles' and 'Near Doubles'. Start with doubles (e.g., 6+6=12) which many students know. Then, explain near doubles by showing how 6+7 is just 6+6+1.

Strategy 3: Count On or Count Back!

For Addition: Count On

Example: 3 + 15

Think: Start at 15 and count on 3 more: 15... 16, 17, 18.

For Subtraction: Count Back

Example: 12 - 3

Think: Start at 12 and count back 3: 12... 11, 10, 9.

Introduce 'Counting On' (for addition) and 'Counting Back' (for subtraction). Emphasize starting with the larger number for 'counting on' to be more efficient.

Whiteboard Wonders: Let's Practice!

Grab your whiteboard and marker!

Solve these problems using a mental strategy. Be ready to share how you solved it!

Problem 1: 9 + 4 = ?

Explain how students will now practice these strategies on their whiteboards. Project problems one by one. Encourage them to try different strategies and be ready to share how they solved it.

Whiteboard Wonders: Next Problem

Problem 2: 15 - 7 = ?

Show the next problem for guided practice.

Whiteboard Wonders: Next Problem

Problem 3: 7 + 8 = ?

Show the next problem for guided practice.

Whiteboard Wonders: Next Problem

Problem 4: 13 - 6 = ?

Show the next problem for guided practice.

Independent Practice: Show What You Know!

Time to be a super math solver on your own!

  • Complete the 'Fact Fluency Practice' worksheet.
  • Try to use our mental strategies.
  • Do your best!

Explain that students will now work on a worksheet independently. Remind them to use the mental strategies they just learned. Encourage them to show their work or write down the strategy they used if it helps them.

Exit Ticket: How Do You Know?

On your exit ticket, answer:

What is one mental strategy you learned today, and how did it help you solve a problem?

Introduce the exit ticket as a quick way to show what they learned. Read the prompt aloud and ask them to write their response.

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Warm Up

Mental Math Challenge!

Solve these problems in your head! Try not to use your fingers or a pencil for now.

  1. 5 + 3 =


  2. 10 - 4 =


  3. 7 + 7 =


  4. 12 - 5 =


  5. 8 + 6 =


  6. 14 - 9 =


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Quiz

Math Fact Masters Quiz

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Answer Key

Math Fact Masters Quiz Answer Key

Questions and Answers

  1. 8 + 5 = ?

    • Answer: 13
    • Strategy Explanation: One strategy is to "Make a Ten." 8 needs 2 more to make 10. You can take 2 from the 5 (leaving 3). So, 8 + 2 = 10, and then add the remaining 3: 10 + 3 = 13.

  2. 14 - 6 = ?

    • Answer: 8
    • Strategy Explanation: One strategy is "Count Back." Start at 14 and count back 6: 14, 13, 12, 11, 10, 9, 8. Another strategy is "Think Addition": What number added to 6 makes 14? 6 + 8 = 14.

  3. 7 + 9 = ?

    • Answer: 16
    • Strategy Explanation: One strategy is to "Make a Ten." 9 needs 1 more to make 10. Take 1 from the 7 (leaving 6). So, 9 + 1 = 10, and then add the remaining 6: 10 + 6 = 16. Another is "Near Doubles": 7 + 7 = 14, so 7 + 8 = 15, and 7 + 9 = 16 (or 8 + 8 = 16, so 7 + 9 is similar).

  4. 11 - 3 = ?

    • Answer: 8
    • Strategy Explanation: One strategy is "Count Back." Start at 11 and count back 3: 11, 10, 9, 8. Another is "Think Addition": What number added to 3 makes 11? 3 + 8 = 11.

  5. 6 + 8 = ?

    • Answer: 14
    • Strategy Explanation: One strategy is to "Make a Ten." 8 needs 2 more to make 10. Take 2 from the 6 (leaving 4). So, 8 + 2 = 10, and then add the remaining 4: 10 + 4 = 14. Another is "Near Doubles": 7 + 7 = 14, and 6 + 8 is also 14.

  6. 16 - 7 = ?

    • Answer: 9
    • Strategy Explanation: One strategy is "Think Addition": What number added to 7 makes 16? 7 + 9 = 16. Another is to "Count Back" from 16 by 7.

  7. 9 + 2 = ?

    • Answer: 11
    • Strategy Explanation: One strategy is "Count On." Start at 9 and count on 2: 9, 10, 11. Another is "Make a Ten": 9 needs 1 more to make 10. Take 1 from the 2 (leaving 1). So, 9 + 1 = 10, and then add the remaining 1: 10 + 1 = 11.

  8. 13 - 5 = ?

    • Answer: 8
    • Strategy Explanation: One strategy is "Think Addition": What number added to 5 makes 13? 5 + 8 = 13. Another is to "Count Back" from 13 by 5.

  9. 4 + 10 = ?

    • Answer: 14
    • Strategy Explanation: This is a straightforward addition to 10. You can also "Count On" from 10 by 4: 10, 11, 12, 13, 14.

  10. 18 - 9 = ?

    • Answer: 9
    • Strategy Explanation: One strategy is "Think Addition": What number added to 9 makes 18? 9 + 9 = 18 (a double fact). So, 18 - 9 = 9.
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Worksheet

Fact Fluency Practice: Addition & Subtraction within 20

Name: _________________________

Date: _________________________

Directions: Solve each problem. Try to use a mental strategy (like 'Make Ten,' 'Doubles,' or 'Count On/Back'). Show your work or explain your strategy if you need to!

Addition Facts

  1. 8 + 7 =





  2. 6 + 5 =





  3. 9 + 3 =





  4. 7 + 9 =





  5. 4 + 8 =





Subtraction Facts

  1. 15 - 8 =





  2. 13 - 6 =





  3. 11 - 4 =





  4. 17 - 9 =





  5. 10 - 7 =





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