Multiply Like a Rock Star: 2-Digit by 1-Digit Multiplication with Partial Products

Mathematics Grades 4th Grade 2:47 Video
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Lesson Description

Learn how to multiply 2-digit numbers by 1-digit numbers using the partial products method! This lesson uses a fun song and real-world examples to help you master multiplication.

Video Resource

2-Digit by 1-Digit Multiplication Song w/ Partial Products

Math Songs by NUMBEROCK

Duration: 2:47
Watch on YouTube

Key Concepts

  • Partial Products
  • Place Value (Tens and Ones)
  • Multiplication
  • Geometric Models

Learning Objectives

  • Students will be able to multiply a 2-digit number by a 1-digit number using the partial products method.
  • Students will be able to explain the connection between place value and the partial products method.
  • Students will be able to solve real-world multiplication word problems.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they already know about multiplication. Review place value (tens and ones). Introduce the idea of breaking down numbers to make multiplication easier.
  • Watch the Numberock Video (5 mins)
    Play the '2-Digit by 1-Digit Multiplication Song w/ Partial Products' video. Encourage students to sing along and pay attention to the examples.
  • Discuss the Video (10 mins)
    After the video, discuss the key concepts. Ask students to explain in their own words what partial products are and how they are used. Review the examples from the video, focusing on the place value aspect.
  • Practice Problems (15 mins)
    Work through several example problems on the board, demonstrating the partial products method. Have students follow along and then try problems on their own. Provide support and guidance as needed.
  • Real-World Application (10 mins)
    Present word problems that require multiplying a 2-digit number by a 1-digit number. Have students solve the problems using the partial products method. Discuss different strategies for checking their answers.

Interactive Exercises

  • Partial Products Matching Game
    Create cards with multiplication problems (e.g., 23 x 4) and cards with the corresponding partial products (e.g., 80 + 12). Students match the problems with their partial products.
  • Word Problem Challenge
    Divide students into groups and give each group a different word problem. Have them solve the problem using the partial products method and present their solution to the class.

Discussion Questions

  • What are partial products and how do they help us multiply?
  • How does place value help us with multiplication?
  • Can you explain how to break down a 2-digit number into tens and ones?
  • In what real-life situations might you use multiplication?

Skills Developed

  • Multiplication Skills
  • Problem-Solving Skills
  • Place Value Understanding
  • Critical Thinking

Multiple Choice Questions

Question 1:

What are partial products?

Correct Answer: The products of multiplying each digit separately

Question 2:

What is 34 x 5 using partial products?

Correct Answer: 150 + 20

Question 3:

What is the first step in solving 28 x 9 using partial products?

Correct Answer: Multiply 8 by 9

Question 4:

What does 'decompose' mean in math?

Correct Answer: To break something down into smaller parts

Question 5:

Which of these uses place value to find partial products?

Correct Answer: Breaking numbers into tens and ones

Question 6:

If you have 6 bags with 25 candies in each, how many candies do you have in total?

Correct Answer: 150

Question 7:

Why is it important to check your work after multiplying?

Correct Answer: To be certain you have the right answer

Question 8:

In the problem 42 x 3, what are the partial products?

Correct Answer: 120 and 6

Question 9:

What does the video suggest you use to see how you arrived at the product?

Correct Answer: Geometric model

Question 10:

If a tray has 34 blueberries, what numbers do we multiply by 5 to find the partial products?

Correct Answer: 30 and 4

Fill in the Blank Questions

Question 1:

The method where we multiply each digit separately is called ______ ______.

Correct Answer: partial products

Question 2:

When multiplying 28 by 9, you first multiply 8 by 9, which equals ____.

Correct Answer: 72

Question 3:

Place value helps us break down numbers into _____ and ones.

Correct Answer: tens

Question 4:

The video suggests checking your work using the ______ operation.

Correct Answer: inverse

Question 5:

Multiplying 30 by 5 gives you a partial product of _____.

Correct Answer: 150

Question 6:

Before you’re done, the video says to ________ your work

Correct Answer: check

Question 7:

When we solve word problems we can use ________ models to visualize how we came to the product

Correct Answer: geometric

Question 8:

Another word for breaking a number down into tens and ones is _________.

Correct Answer: decompose

Question 9:

9 bags with 28 cans in each bag means we need to __________ 28 and 9.

Correct Answer: multiply

Question 10:

When multiplying with partial products, we add the smaller products together to find the _________.

Correct Answer: total product

Educational Standards

4.N.2.2:Multiply 3-digit by 1-digit and 2-digit by 2-digit whole numbers, using various strategies, including but not limited to standard algorithms. 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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