Question: what is the greatest common factor of two and three?
Answer: Multiply the circled numbers together. This is the greatest common factor! In the example, please be patient] gcf(18,36,90)=2⋅3⋅3=18 gcf ( 18 , 36 , 90 ) = 2 ⋅ 3 ⋅ 3 = 18 .