When you look at the expression, 54 + 27, what do the two addends have in common?The first thing I notice is that 54 = 2(27), which means that 27 is a factor of both. Since, 27 is actually one of the addends, it's the greatest factor of 27 and therefore the greatest common factor. So,54 + 27 = 27(2+1)54 + 27 = 27(3)
