Mathematics
Grade 7
15 min
Prime factorization
Prime factorization
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Define prime and composite numbers.
Identify prime numbers up to 100.
Explain the concept of prime factorization.
Use factor trees to find the prime factorization of a composite number.
Use the division method to find the prime factorization of a composite number.
Write the prime factorization of a number using exponential notation.
Ever wondered how numbers are built from their most basic 'ingredients'? 🤔 Just like molecules are made of atoms, numbers are made of primes!
In this lesson, you'll discover how to break down any composite number into its unique set of prime building blocks. Understanding prime factorization is a fundamental skill in number theory and will help you simplify fractions, find common multiples, and even understand...
2
Key Concepts & Vocabulary
TermDefinitionExample
FactorA factor is a whole number that divides another whole number exactly, with no remainder.The factors of 12 are 1, 2, 3, 4, 6, and 12 because each of these numbers divides 12 evenly.
Prime NumberA prime number is a natural number greater than 1 that has exactly two distinct positive factors: 1 and itself.The number 7 is a prime number because its only factors are 1 and 7. Other examples include 2, 3, 5, 11, 13.
Composite NumberA composite number is a natural number greater than 1 that has more than two distinct positive factors (i.e., it is not prime).The number 10 is a composite number because its factors are 1, 2, 5, and 10. Other examples include 4, 6, 8, 9, 12.
Prime FactorA prime factor is a factor of a number that is also a prime number.For the number 12, i...
3
Core Formulas
Fundamental Theorem of Arithmetic
Every integer greater than 1 is either a prime number itself or can be represented as a product of prime numbers, and this representation is unique, up to the order of the factors.
This rule tells us that prime numbers are the 'building blocks' of all other whole numbers, and there's only one way to build each number from primes (if we ignore the order).
Prime Factorization using Exponents
When writing the prime factorization of a number, if a prime factor appears multiple times, you can use exponents to simplify the notation: $N = p_1^{a_1} \times p_2^{a_2} \times \dots \times p_k^{a_k}$
This rule provides a concise way to write prime factorizations. For example, instead of $2 \times 2 \times 2 \times 3$, we write $2^3 \times...
5 more steps in this tutorial
Sign up free to access the complete tutorial with worked examples and practice.
Sign Up Free to ContinueSample Practice Questions
Challenging
The number 360 is written in its prime factorization as $2^a \times 3^b \times 5^c$. What is the value of a + b + c?
A.6
B.7
C.5
D.8
Challenging
What is the largest prime factor of the number 231?
A.3
B.7
C.11
D.231
Challenging
A number's prime factorization is $p^2 \times q$, where p and q are distinct prime numbers. If the number is greater than 100, what is the smallest possible value of this number?
A.108 (3^3 x 4)
B.125 (5^3)
C.147 (3 x 7^2)
D.132 (2^2 x 3 x 11)
Want to practice and check your answers?
Sign up to access all questions with instant feedback, explanations, and progress tracking.
Start Practicing Free