# Ch 4: ACCESS Math Unit 4: Number Theory

### About This Chapter

## How It Works:

- Identify the lessons in the ACCESS Math Number Theory chapter with which you need help.
- Find the corresponding video lessons with this companion course chapter.
- Watch fun videos that cover the number theory topics that you need to learn or review.
- Complete the quizzes to test your understanding.
- If you need additional help, rewatch the videos until you've mastered the material or submit a question for one of our instructors.

## Students will learn:

- Divisibility rules and how to divide by numbers up to 10
- How to identify prime and composite numbers
- What the prime factors of a number are
- How to determine the greatest common factor
- Methods to find the least common multiple

*ACCESS Math is a registered trademark of Houghton Mifflin Harcourt, which is not affiliated with Study.com.*

### 1. Divisibility by 2, 3, and 4

In this video lesson, you will learn what it means to be divisible. Also, you'll see what numbers are divisible by 2, 3, and 4. You will also learn how you can check if something is divisible by these numbers.

### 2. Divisibility by 5, 6, and 7

In this video lesson, we will see what numbers can be divided equally by 5, 6, and 7. Learn the pattern that you can use to find other numbers divisible by 5, 6 and 7. Learn how you can visualize divisibility.

### 3. Divisibility by 8, 9, and 10

In this video lesson, we will see what numbers are divisible by 8, 9, and 10. You will learn how you can figure out these numbers yourself. Learn what it means to be divisible.

### 4. Identifying Prime & Composite Numbers

In this video lesson, you will learn how to identify both prime and composite numbers. You will also learn what makes the numbers unique, as well as the characteristics of both these types of numbers.

### 5. How to Find the Prime Factorization of a Number

The prime factorization of a number involves breaking that number down to its smallest parts. This lesson will show you two different ways to discover the prime factorization of any number.

### 6. How to Find the Greatest Common Factor

If the factors of a number are the different numbers that you can multiply together to get that original number, then the greatest common factor of two numbers is just the biggest one that both have in common. See some examples of what I'm talking about here!

### 7. How to Find the Least Common Multiple

The least common multiple of two numbers is the smallest number that can be divided evenly by your two original numbers. See some examples of what I'm talking about here!

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### Other Chapters

Other chapters within the ACCESS Math: Online Textbook Help course

- ACCESS Math Unit 1: Number Concepts
- ACCESS Math Unit 2: Introduction to Algebra
- ACCESS Math Unit 3: Decimals
- ACCESS Math Unit 5: Fractions & Mixed Numbers
- ACCESS Math Unit 6: Ratios, Proportions & Percents
- ACCESS Math Unit 7: Data & Statistics
- ACCESS Math Unit 8: Geometry
- ACCESS Math Unit 9: Area & Volume
- ACCESS Math Unit 10: Probability
- ACCESS Math Unit 11: Integers
- ACCESS Math Unit 12: More Algebra