Example: 30 and 42
The factors of 30 are:
1, 2, 3, 5, 6, 10, 15, 30
The factors of 42 are:
1, 2, 3, 6, 7, 14, 21, 42
The common factors are:
1, 2, 3, 6
The Greatest Common Factor:
GCF = 6
The greatest common factor of two numbers has to show up on the lists of factors of both numbers.
The numbers on both of those lists are 3, 5 and 7. The GCF is 105.
In order to find the common factors of 2 numbers, it is easiest to first list their factors. The factors of 36 are: 1, 2, 3, 4, 6, 9, 12, 18 and 36 The factors of 24 are: 1, 2, 3, 4, 6, 8, 12 and 24. The common factors are the numbers that appear in both lists. These are 1, 2, 3, 4, 6 and 12.
Factors refer to whole numbers, not decimals.
One needs the composite number before he can find its factors. Thus the solution I shall give is ∞.
-- List all the factors of the first number. -- List all the factors of the second number. -- Place the lists side-by-side. -- Look to see what numbers are on both lists. There may be several of them. They are the "common factors" of the two original numbers.
List the factors. 1,2,3,4,6,12 1,2,3,4,6,8,12,24 Write down the numbers on both lists. 1,2,3,4,6,12
List the factors of each of the numbers in the set. Write down the numbers that appear on all the lists. Choose the largest one.
-- The numerator is a number. -- The denominator is a number. -- Together, they comprise two numbers. Their gcf is found by using the same process you use to find the gcf of any other two numbers: -- List all the factors of the first number. -- List all the factors of the other number. -- Compare the lists. Any number that appears on both lists is a common factor of the two numbers. -- The greatest of those is the greatest common factor of the two numbers.
At least two or more numbers are needed to find their LCM
"Common" means " belonging to two or more quantities." List the factors of the numbers you are comparing. The common factors appear on all the lists.
-- List all the factors of the first number.-- List all the factors of the second number.-- Find any factors that appear on both lists.-- The highest one of those is the HCF of the two original numbers.
The greatest common factor of two numbers has to show up on the lists of factors of both numbers.
You won't find common factors by using lists of multiples. The least common factor of any set of integers is 1, no matter what you use.
Write down the factors of the numbers you're comparing. Choose the largest number that appears on both lists.
All numbers have factors. Some numbers have some of the same factors as other numbers. These are known as common factors. One way to find them is to list all the factors of a set of numbers. Example 30 and 42 1, 2, 3, 5, 6, 10, 15, 30 1, 2, 3, 6, 7, 14, 21, 42 1, 2, 3 and 6 appear on both lists. They are the common factors of 30 and 42.
To find the GCF or the LCM of a set of numbers, it is sometimes practical to write out lists of the factors or multiples as the case may be and compare them. This is known as the listing method.