What is the greatest common factor for 12 and 15?

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Sariah Glover · Accepted Answer

Step 1The GCF of 12 and 15 is 3.One way to find this is to break down these two numbers into their &#039; factorisations:      12    =    2    ×    2    ×    3        15    =    3    ×    5  We see that the only common factor (greater than 1) is 3, so that is the greatest common factor. If the two numbers had more than one &#039; factor in common, you would multiply them together to find the GCF.Another method, which does not require us to factor both of the numbers first goes as follows:Divide the larger number by the smaller number to give a quotient and remainder.If the remainder is zero then the smaller number is the GCF.Otherwise repeat with the smaller number and the remainder.In our example:            15      12        =    1   with remainder 3            12      3        =    4   with remainder 0So the GCF is 3.

What is the greatest common factor for 12 and 15?

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