lenny

Add/Subtract Race

Lesson Plan

Add/Subtract Race

Students will accurately solve 3-digit addition and subtraction problems, including those requiring regrouping, within a small group setting.

Mastering 3-digit addition and subtraction is crucial for developing strong number sense and is a foundational skill for more complex math concepts. This activity provides targeted practice in a supportive group environment.

Audience

3rd Grade Students

Time

30 minutes

Approach

Game-based learning

Materials

Whiteboards or scratch paper, Dry-erase markers, Erasers, Add/Subtract Race Activity Cards, and Answer Key: Add/Subtract Race

Prep

Activity Setup

10 minutes

Step 1

Introduction (5 minutes)

5 minutes

  • Greet the small group and explain that they will be playing a fun math game called 'Add/Subtract Race'.
    - Briefly review the concepts of 3-digit addition and subtraction, emphasizing regrouping where necessary. Ask a quick warm-up question to gauge understanding.
    - Explain that the goal is to correctly solve as many problems as possible as a team.

Step 2

Game Rules & Setup (5 minutes)

5 minutes

  • Explain the game: Students will take turns drawing a card, solving the problem on their whiteboard, and then showing their work to the group.
    - The rest of the group will check the answer using the Answer Key: Add/Subtract Race. If correct, the group gets a point (or simply moves on). If incorrect, they can work together to find the correct answer.
    - Emphasize collaboration and helping each other learn, rather than just racing.
    - Distribute whiteboards, markers, and erasers. Place the shuffled Add/Subtract Race Activity Cards face down in the center.

Step 3

Play the Game (15 minutes)

15 minutes

  • Facilitate the game, ensuring each student gets a turn.
    - Observe students' strategies and provide immediate feedback or gentle guidance as needed, especially on regrouping.
    - Encourage students to articulate their thinking process.
    - Keep the pace engaging but allow for discussion and peer teaching.

Step 4

Wrap-up & Review (5 minutes)

5 minutes

  • Call time and discuss how many problems the group solved.
    - Ask students what they found challenging and what they found easy.
    - Briefly review one or two of the problems that were particularly tricky for the group, using the Answer Key: Add/Subtract Race as a guide.
    - Praise their teamwork and effort.
lenny
0 educators
use Lenny to create lessons.

No credit card needed

Slide Deck

Ready, Set, Math!

Today, we're going on an 'Add/Subtract Race' to become 3-digit number champions!

Welcome students to the small group. Introduce the day's math challenge!

Adding Three-Digit Numbers

  • Add the ones first. Regroup if needed!
  • Add the tens next, remembering any regrouped tens. Regroup if needed!
  • Add the hundreds last, remembering any regrouped hundreds.

Quickly review what 3-digit addition means and how regrouping works. Use a simple example if helpful.

Subtracting Three-Digit Numbers

  • Start in the ones place. Can you subtract?
  • If not, you'll need to regroup (borrow) from the tens place!
  • Move to the tens, then the hundreds, regrouping whenever necessary.

Quickly review what 3-digit subtraction means and how regrouping (borrowing) works. Use a simple example if helpful.

The Race Rules!

  1. Pick a card!
  2. Solve the problem on your whiteboard.
  3. Show your work to your team.
  4. Team checks the answer together.
  5. Work together if you need to!

Let's get ready to race and learn!

Explain the game mechanics as outlined in the lesson plan. Emphasize teamwork.

lenny

Activity

Add/Subtract Race Activity Cards

Cut out these cards and place them face down for students to draw during the game.

Card 1

  345
+ 123
-----

Card 2

  587
- 243
-----

Card 3

  268
+ 154
-----

Card 4

  732
- 418
-----

Card 5

  471
+ 289
-----

Card 6

  600
- 175
-----

Card 7

  198
+ 325
-----

Card 8

  850
- 362
-----

Card 9

  567
+ 233
-----

Card 10

  905
- 489
-----

Card 11

  314
+ 497
-----

Card 12

  721
- 356
-----
lenny
lenny

Answer Key

Answer Key: Add/Subtract Race

Here are the solutions to the activity cards. Encourage students to show their work and explain their regrouping steps.

Card 1: 345 + 123

  • Solution: 468
  • Step-by-step:
    • Ones place: 5 + 3 = 8
    • Tens place: 4 + 2 = 6
    • Hundreds place: 3 + 1 = 4

Card 2: 587 - 243

  • Solution: 344
  • Step-by-step:
    • Ones place: 7 - 3 = 4
    • Tens place: 8 - 4 = 4
    • Hundreds place: 5 - 2 = 3

Card 3: 268 + 154

  • Solution: 422
  • Step-by-step:
    • Ones place: 8 + 4 = 12 (Write 2, regroup 1 ten to the tens place)
    • Tens place: 6 + 5 + 1 (regrouped) = 12 (Write 2, regroup 1 hundred to the hundreds place)
    • Hundreds place: 2 + 1 + 1 (regrouped) = 4

Card 4: 732 - 418

  • Solution: 314
  • Step-by-step:
    • Ones place: You can't subtract 8 from 2. Regroup 1 ten from the tens place (3 tens become 2 tens, 2 ones become 12 ones). 12 - 8 = 4
    • Tens place: 2 - 1 = 1
    • Hundreds place: 7 - 4 = 3

Card 5: 471 + 289

  • Solution: 760
  • Step-by-step:
    • Ones place: 1 + 9 = 10 (Write 0, regroup 1 ten to the tens place)
    • Tens place: 7 + 8 + 1 (regrouped) = 16 (Write 6, regroup 1 hundred to the hundreds place)
    • Hundreds place: 4 + 2 + 1 (regrouped) = 7

Card 6: 600 - 175

  • Solution: 425
  • Step-by-step:
    • Ones place: You can't subtract 5 from 0. Go to the tens place, but it's also 0. Go to the hundreds place. Regroup 1 hundred from 600 (6 hundreds become 5 hundreds, 0 tens become 10 tens). Now regroup 1 ten from 10 tens (10 tens become 9 tens, 0 ones become 10 ones). 10 - 5 = 5
    • Tens place: 9 - 7 = 2
    • Hundreds place: 5 - 1 = 4

Card 7: 198 + 325

  • Solution: 523
  • Step-by-step:
    • Ones place: 8 + 5 = 13 (Write 3, regroup 1 ten to the tens place)
    • Tens place: 9 + 2 + 1 (regrouped) = 12 (Write 2, regroup 1 hundred to the hundreds place)
    • Hundreds place: 1 + 3 + 1 (regrouped) = 5

Card 8: 850 - 362

  • Solution: 488
  • Step-by-step:
    • Ones place: You can't subtract 2 from 0. Regroup 1 ten from the tens place (5 tens become 4 tens, 0 ones become 10 ones). 10 - 2 = 8
    • Tens place: You can't subtract 6 from 4. Regroup 1 hundred from the hundreds place (8 hundreds become 7 hundreds, 4 tens become 14 tens). 14 - 6 = 8
    • Hundreds place: 7 - 3 = 4

Card 9: 567 + 233

  • Solution: 800
  • Step-by-step:
    • Ones place: 7 + 3 = 10 (Write 0, regroup 1 ten to the tens place)
    • Tens place: 6 + 3 + 1 (regrouped) = 10 (Write 0, regroup 1 hundred to the hundreds place)
    • Hundreds place: 5 + 2 + 1 (regrouped) = 8

Card 10: 905 - 489

  • Solution: 416
  • Step-by-step:
    • Ones place: You can't subtract 9 from 5. Go to the tens place, but it's 0. Go to the hundreds place. Regroup 1 hundred from 905 (9 hundreds become 8 hundreds, 0 tens become 10 tens). Now regroup 1 ten from 10 tens (10 tens become 9 tens, 5 ones become 15 ones). 15 - 9 = 6
    • Tens place: 9 - 8 = 1
    • Hundreds place: 8 - 4 = 4

Card 11: 314 + 497

  • Solution: 811
  • Step-by-step:
    • Ones place: 4 + 7 = 11 (Write 1, regroup 1 ten to the tens place)
    • Tens place: 1 + 9 + 1 (regrouped) = 11 (Write 1, regroup 1 hundred to the hundreds place)
    • Hundreds place: 3 + 4 + 1 (regrouped) = 8

Card 12: 721 - 356

  • Solution: 365
  • Step-by-step:
    • Ones place: You can't subtract 6 from 1. Regroup 1 ten from the tens place (2 tens become 1 ten, 1 one becomes 11 ones). 11 - 6 = 5
    • Tens place: You can't subtract 5 from 1. Regroup 1 hundred from the hundreds place (7 hundreds become 6 hundreds, 1 ten becomes 11 tens). 11 - 5 = 6
    • Hundreds place: 6 - 3 = 3
lenny
lenny