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Determine the prime factors for both numbers
18 = 2 x 3 x 3
21 = 3 x 7
As 3 is the only factor common to both numbers then 3 is the Lowest Common Factor and the Highest Common Factor.
NOTE : In general questions are asked for the HighestCommon Factor and/or the Least (or Lowest Common Multiple.
In case the LCM is required , then this is the product of the highest power of each prime factor. Hence, LCM = 2 x 32 x 7 = 2 x 9 x 7 = 126
What else can I help you with?
Lowest common multiple of 18 and 21?
The Least Common Multiple of 18 and 21 is 126.
Which number goes into 21 and 18?
The highest common factor of 21 and 18 is 3
What is the highest common factor of 18 and 21?
Factors of 18 are 3,3,& 2. Factors of 21 are 3 & 7 One lot of '3' is common to both so '3' is the HCF.
Three 3 is a common factor of 21 and 22?
Three (3) is a common factor of 21 and 22.
What is the greatest common factor for 21 and 36?
The factors of 21 are 1, 3, 7, and 21. The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, and 36. The factors they have in common are 1 and 3, the largest of which is 3, so 3 is the greatest common factor. Or, you can calculate the greatest common factor by looking at the prime factors. The prime factors of 21 are 3 and 7. The prime factors of 36 are 2, 2, 3, and 3. The prime factors they have in common are a single 3, so 3 is the greatest common factor.
What is the lowest common factor of 12 18 and 21?
The least common factor of any set of integers is 1.
The greater common factor of 18 21?
The greatest common factor of 18 and 21 is 3.
What is the lowest common factor of 6 and 21?
The least common factor is: 1
Lowest common multiple of 18 and 21?
The Least Common Multiple of 18 and 21 is 126.
What is the greatest common factor of 9 18 and 21?
The Greatest Common Factor of 9, 18, 21: 3
What is the lowest common factor of 21 and 28?
1 and 7
What is the lowest common factor for 9 21 and 24?
3
What is a lowest common denominator for 15 21 27?
945 is the lowest common denominator. 3 is the greatest common factor.
What is the lowest common multiple 18 and 21?
126
What is the least common factor of 18 21 and 36?
The factors of 18 are 1, 2, 3, 6, 9, and 18. The factors of 21 are 1, 3, 7, and 21. The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, and 36. The factors they have in common are 1 and 3. So, the least (or lowest) common factor is 1. Note: The least common factor of two or more positive integers will always be 1.
What is the lowest common multiple of 18 and 21?
126The Least Common Multiple (LCM) for 18 21 is 126.It is 126
What is the least common factor of 18 and 21?
The factors of 18 are 1, 2, 3, 6, 9, and 18. The factors of 21 are 1, 3, 7, and 21. The common factors are 1 and 3. Therefore, the least common factor (the smallest common factor) is 1. Factorizations: 18-3x3x2 21-7x3
