You need at least two numbers to find a GCF.
There cannot be a greatest common factor (GCF) of just one number. To be common there need to be at least two numbers. If you find all the factors of two or more numbers, and you find some factors are the same ("common"), then the largest of those common factors is the Greatest Common Factor.
What are the common factors of 15, 25 and 40
The factors of 40 are 1,2,4,5,8,10,20 and 40. For them to be common, they need to be compared to another set of factors.
The common factors of 30 and 40 are 1, 2, 5, 10
The greatest common factor (GCF) of 10, 25, and 40 is 5. To find the GCF, you need to determine the factors of each number and then identify the largest factor that is common to all three numbers. The factors of 10 are 1, 2, 5, and 10. The factors of 25 are 1, 5, 25. The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40. The largest factor that is common to all three numbers is 5, making it the greatest common factor.
Common factors are those that can be divided into two different numbers. For 4 and 40, their common factors are: 1, 2, 4, -1, -2, -4. Of these, the largest number is 4 (and this is therefore the greatest common factor).
The common factors of 36 and 40 are 1,2 and 4.
The common factors of 40 and 135 are 1 and 5.
The common factors of 40 and 2015 are 1 and 5.
The common factors of 18 and 40 are: 1, 2.
Common factors of 38 and 40 are 1 and 2.
The factors of 22 are 1, 2, 11, and 22.The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40.The largest factor they have in common is 2, therefore 2 is the greatest common factor.Or, you can use the prime factors to determine the greatest common factor.The prime factors of 22 are 2 and 11.The prime factors of 40 are 2, 2, 2, and 5.The prime factors they have in common are a single 2, so 2 is the greatest common factor.The GCF is 2.