There cannot be a common factor 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.
Common factors of 55 and 78 are: 1.
The common factors of 55 and 99 are: 1 and 11
The common factors of 55 and 80 are 1 and 5
Factors of 25 are 1, 5, and 25. Factors of 55 are 1, 5, 11, and 55. The common factors of 25 and 55 are 1 and 5.
The factors of 55 are 1, 5, 11 and 55. For them to be common, they need to be compared to another set of factors.
The common factors of 55 and 88 are: 1 and 11.
The positive integer common factors of 11 and 55 and 1 and 11.
The common factors of 44 and 55 are: 1 and 11
The factors of 33 are 1,3,11,33 The factors of 55 are 1,5,11,55 Hence common factors are 1, & 11. as these two numbers appear in each list of factors.
Factors of 55 are: 1, 5, 11, and 55 Factors of 99 are: 1, 3, 9, 11, 33, and 99 "Common" factors are numbers that are factors of both. Common factors of 55 and 99 are: 1 and 11 .
The common factors are: 1, 5
The common factors are: 1, 5