Is 1 a common factor?On the tv show "Are You Smarter Than A Fifth Grader" this guy had a question that was how many common factors do 28 and 32...

The producers were right. 28 has factors of 1,2,4,7,14 and 28 while 32 has faxtors of 1,2,4,8,16,32.

As you can see. 32 and 28 have similar factors of 1,2 and 4. 1 is considered a factor as all numbers under the sun have a factor of 1, or you could say a common divisor tool.