## Elementary Algebra

The factors of $48$ are: {$1,2,3,4,6,8,12,16,24,48$} The factors of $60$ are: {$1,2,3,4,5,6,10,12,15,20,30,60$} The factors of $84$ are: {$1,2,3,4,6,7,12,14,21,28,42,84$} Amongst all three sets, the greatest common factor is $12$.