Enter GCF or LCM numbers:
Determine GCF(18,21)
GCF = Largest factor that divides numbers
Determine the factors for 18
1,2,3,6,9,18
Determine the factors for 21
1,3,7
List the common factors
1,3
GCF(18,21) = 3
GCF(18,21) = 3
Evaluate GCF
Since GCF ≠ 1, they are not relatively prime (co-prime)
Since GCF ≠ 1 and have a difference of two, the numbers are not twin prime
Calculate LCM for the following
(18,21)
List the first few multiples for 18
18,36,54,72,90,108,126,144,162,180
List the first few multiples for 21
21,42,63,84,105,126,147,168,189
LCM is the smallest common number:
LCM(18,21) is 126
LCM(18,21) is 126
Common Core State Standards In This Lesson
6.NS.B.4
What is the Answer?
LCM(18,21) is 126
How does the Greatest Common Factor and Least Common Multiple Calculator work?
Free Greatest Common Factor and Least Common Multiple Calculator - Given 2 or 3 numbers, the calculator determines the following:
* Greatest Common Factor (GCF) using Factor Pairs
* Rewrite Sum using the Distributive Property and factoring out the GCF
* Least Common Multiple (LCM) / Least Common Denominator (LCD) using Factor Pairs
* GCF using the method of Successive Division
* GCF using the Prime Factorization method
* Determine if the numbers are coprime and twin prime
This calculator has 3 inputs.
* Greatest Common Factor (GCF) using Factor Pairs
* Rewrite Sum using the Distributive Property and factoring out the GCF
* Least Common Multiple (LCM) / Least Common Denominator (LCD) using Factor Pairs
* GCF using the method of Successive Division
* GCF using the Prime Factorization method
* Determine if the numbers are coprime and twin prime
This calculator has 3 inputs.
What 11 concepts are covered in the Greatest Common Factor and Least Common Multiple Calculator?
- division
- separate a number into parts
- division
- separate a number into parts
- factor
- a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n.
- greatest common factor
- largest positive integer dividing a set of integers
- greatest common factor and least common multiple
- least common multiple
- Given 2 numbers a and b, the least common multiple LCM is the smallest positive integer that is divisible by both. It is commonly denoted as LCM(a, b)
- minimum
- the least or lowest amount possible or attained
- multiple
- the product of any quantity and an integer
- number
- an arithmetical value, expressed by a word, symbol, or figure, representing a particular quantity and used in counting and making calculations and for showing order in a series or for identification. A quantity or amount.
- prime factorization
- the prime numbers that divide that integer exactly
- remainder
- The portion of a division operation leftover after dividing two integers
