greatest common factor=gcf
least common multule=lcm
with 12 and 16
factors of 12=2 times 2 times 3
factors of 16=2 times 2 times 2 times 2
greates common factor is 2 times 2=4
least common multiple means all factors combined minus repeats or 2 times 2 times 2 times 2 time 3=48