Cracking the Code: Breaking Apart 3-Digit Addition!

Mathematics Grades 4th Grade 3:41 Video
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Lesson Description

Learn how to break down 3-digit addition problems using place value to make them easier to solve! We'll explore hundreds, tens, and ones to become addition masters.

Video Resource

Breaking apart 3-digit addition problems | 2nd grade | Khan Academy

Khan Academy

Duration: 3:41
Watch on YouTube

Key Concepts

  • Place Value (Hundreds, Tens, Ones)
  • Decomposing Numbers
  • Addition Strategies

Learning Objectives

  • Students will be able to identify the place value of digits in a 3-digit number.
  • Students will be able to decompose 3-digit numbers into hundreds, tens, and ones.
  • Students will be able to use place value to break apart and solve 3-digit addition problems.

Educator Instructions

  • Introduction (5 mins)
    Begin by reviewing place value (hundreds, tens, ones) with the class. Ask students to provide examples of numbers and identify the value of each digit. Briefly introduce the idea that large addition problems can be easier to solve by breaking them down.
  • Video Viewing (10 mins)
    Play the Khan Academy video "Breaking apart 3-digit addition problems | 2nd grade | Khan Academy". Instruct students to pay close attention to how Sal breaks down the addition problems using place value.
  • Guided Practice (15 mins)
    Work through examples similar to those in the video on the board. For example, present the problem 245 + 321. Guide students to break down each number: 200 + 40 + 5 and 300 + 20 + 1. Then, add the hundreds, tens, and ones separately (200+300, 40+20, 5+1) before combining the sums.
  • Independent Practice (15 mins)
    Provide students with a worksheet containing 3-digit addition problems. Instruct them to use the breaking-apart strategy to solve each problem. Circulate the room to provide assistance and answer questions.
  • Wrap-up (5 mins)
    Review the key concepts of the lesson. Have students share their strategies and discuss any challenges they encountered. Emphasize the importance of understanding place value in addition.

Interactive Exercises

  • Place Value Breakdown
    Write a 3-digit number on the board (e.g., 472). Ask students to come up and write the number in expanded form (400 + 70 + 2) and identify the value of each digit (4 hundreds, 7 tens, 2 ones).
  • Addition Race
    Divide the class into teams. Present a 3-digit addition problem. The first team to correctly solve the problem using the breaking-apart strategy wins a point.

Discussion Questions

  • Why is understanding place value important for solving addition problems?
  • How does breaking apart numbers make addition easier?
  • Can you think of other strategies for solving addition problems?

Skills Developed

  • Place Value Understanding
  • Problem-Solving Strategies
  • Mental Math Skills

Multiple Choice Questions

Question 1:

What is the value of the digit '7' in the number 673?

Correct Answer: 70

Question 2:

Which of these shows 528 broken apart by place value?

Correct Answer: 500 + 20 + 8

Question 3:

What is 300 + 50 + 2?

Correct Answer: 352

Question 4:

If you break apart 456 and 231, what hundreds would you add together?

Correct Answer: 400 + 200

Question 5:

When adding 289 + 110 by breaking apart, what tens would you add?

Correct Answer: 80 + 10

Question 6:

What is the first step in breaking apart 624 + 153?

Correct Answer: Break each number into hundreds, tens, and ones

Question 7:

Which problem is the same as 345 + 123?

Correct Answer: 300 + 40 + 5 + 100 + 20 + 3

Question 8:

You broke apart 781 + 205. Which of these is NOT something you would add?

Correct Answer: 7 + 2

Question 9:

If you add 500 + 20 + 9 + 100 + 60 + 0, what is the sum?

Correct Answer: 689

Question 10:

Breaking apart helps you with addition because...

Correct Answer: It helps you understand place value

Fill in the Blank Questions

Question 1:

The digit in the hundreds place of the number 832 is ____.

Correct Answer: 8

Question 2:

500 + 30 + 7 is the same as the number ____.

Correct Answer: 537

Question 3:

Breaking apart a number means separating it by its _____ value.

Correct Answer: place

Question 4:

In the number 914, the 1 represents ____ tens.

Correct Answer: 1

Question 5:

To add 621 + 258 by breaking apart, you first add 600 and ____.

Correct Answer: 200

Question 6:

In 3-digit addition, you add the hundreds, the _____, and the ones.

Correct Answer: tens

Question 7:

400 + 20 + 5 is the expanded form of the number ______.

Correct Answer: 425

Question 8:

When you break apart numbers, you are using their _____ to help you add.

Correct Answer: digits

Question 9:

In the number 742, the digit 2 is in the ______ place.

Correct Answer: ones

Question 10:

Breaking apart addition makes it easier to do ______ math.

Correct Answer: mental

Educational Standards

4.N.1.2:Use place value to describe whole numbers between 1,000 and 1,000,000 in terms of millions, hundred thousands, ten thousands, thousands, hundreds, tens, and ones with written, standard, and expanded forms. 4.N.2.4:Apply and analyze models to solve multi-step problems requiring the use of addition, subtraction, and multiplication of multi-digit whole numbers. Use various strategies, including the relationship between operations, the use of appropriate technology, and the context of the problem to assess the reasonableness of results.

Teaching Materials

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