# Ch 5: WEST Middle Grades Math: Number Theory

### About This Chapter

## WEST Math: Number Theory - Chapter Summary

The number theory chapter will examine the many different characteristics of numbers. As you prepare for the WEST Middle Grades Math exam, you will review things such as the different categories of numbers and the process of finding factors and multiples. By the end of the chapter you will have reviewed:

- Prime, composite, and odd and even numbers
- Prime factorization
- Greatest common factor
- Least common multiple
- Word problems involving number theory

Make sure to take each lesson quiz so that you can practice our test-taking strategies. These practice quizzes will help you learn to budget your time, as well.

### Objectives of the WEST Math: Number Theory Chapter

The new WEST Math exam will evaluate your knowledge across four domains: number sense and operations; algebra and functions, measurement and geometry; and statistics, probability, and discrete mathematics. This chapter connects to the number sense domain. This domain will be about 17% of the 150 multiple-choice questions. You will have 4 hours and 15 minutes to answer all of the questions. The exam is computer based.

### 1. What Are Prime Numbers? - Definition & Examples

Learn the definition of prime numbers and composite numbers while working through a few examples of how to identify them. Then expand your knowledge by learning three rules that help you determine whether or not a number is prime.

### 2. What Are Composite Numbers? - Definition & Examples

In this lesson, you'll learn what composite numbers are and briefly touch on prime numbers. You'll also learn a couple of rules about composite numbers. Then, you can test your new knowledge with a brief quiz.

### 3. What Are Odd & Even Numbers? - Definition & Examples

In this lesson, you'll learn what odd and even numbers are with the help of some visual aids. You'll also learn some interesting properties of odd and even numbers. Then, you can test your new knowledge with a brief quiz.

### 4. 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.

### 5. Finding the Prime Factorization with Exponents

After watching this video lesson, you will be able to factor any number using just prime numbers and exponents. Learn how to break apart any number you are given. Then, test your new knowledge with some examples.

### 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!

### 8. Using Prime Factorizations to Find the Least Common Multiples

Finding the least common multiple can seem like a lot of work. But we can use prime factorization as a shortcut. Find out how and practice finding least common multiples in this lesson.

### 9. Word Problems: Greatest Common Factor & Least Common Multiple

In this video lesson, you will learn what kinds of word problems you can expect to see that involve the greatest common factor or the least common multiple. Learn what you need to do to understand these problems and then to solve them.

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### Other Chapters

Other chapters within the WEST Middle Grades Mathematics (203): Practice & Study Guide course

- WEST Middle Grades Math: Basic Arithmetic Operations
- WEST Middle Grades Math: Solving Math Word Problems
- WEST Middle Grades Math: Properties of Numbers
- WEST Middle Grades Math: Estimating & Rounding
- WEST Middle Grades Math: Roots & Radical Expressions
- WEST Middle Grades Math: Exponents & Exponential Expressions
- WEST Middle Grades Math: Scientific Notation
- WEST Middle Grades Math: Simplifying Whole Number Expressions
- WEST Middle Grades Math: Integers
- WEST Middle Grades Math: Rational Numbers
- WEST Middle Grades Math: Introduction to Fractions
- WEST Middle Grades Math: Operations with Fractions
- WEST Middle Grades Math: Introduction to Decimals
- WEST Middle Grades Math: Operations with Decimals
- WEST Middle Grades Math: Percents
- WEST Middle Grades Math: Money & Consumer Math
- WEST Middle Grades Math: Number Patterns & Sequences
- WEST Middle Grades Math: Properties of Functions
- WEST Middle Grades Math: Graphing Functions
- WEST Middle Grades Math: Negative Numbers
- WEST Middle Grades Math: Absolute Value
- WEST Middle Grades Math: Inequalities
- WEST Middle Grades Math: Factoring
- WEST Middle Grades Math: Monomials & Polynomials
- WEST Middle Grades Math: Writing Algebraic Expressions
- WEST Middle Grades Math: Basic Algebraic Expressions
- WEST Middle Grades Math: Algebraic Distribution
- WEST Middle Grades Math: Writing & Solving One-Step Equations
- WEST Middle Grades Math: Writing & Solving Two-Step Equations
- WEST Middle Grades Math: Simplifying & Solving Rational Expressions
- WEST Middle Grades Math: The Coordinate Graph
- WEST Middle Grades Math: Linear Equations
- WEST Middle Grades Math: Systems of Linear Equations
- WEST Middle Grades Math: Rates, Ratios & Proportions
- WEST Middle Grades Math: Measurements
- WEST Middle Grades Math: Perimeter & Area
- WEST Middle Grades Math: Polyhedrons & Geometric Solids
- WEST Middle Grades Math: Symmetry, Similarity & Congruence
- WEST Middle Grades Math: Properties of Lines
- WEST Middle Grades Math: Angles
- WEST Middle Grades Math: Triangles
- WEST Middle Grades Math: Triangle Theorems & Proofs
- WEST Middle Grades Math: Similar Polygons
- WEST Middle Grades Math: The Pythagorean Theorem
- WEST Middle Grades Math: Quadrilaterals
- WEST Middle Grades Math: Circles
- WEST Middle Grades Math: Circular Arcs & Measurement
- WEST Middle Grades Math: Transformations
- WEST Middle Grades Math: Data & Graphs
- WEST Middle Grades Math: Statistics
- WEST Middle Grades Math: Data Collection
- WEST Middle Grades Math: Samples & Populations
- WEST Middle Grades Math: Probability
- WEST Middle Grades Math: Sets
- WEST Middle Grades Mathematics Flashcards