Can someone check this for me :
Find the gcf for each of the following groups of numbers: 36,64, and 180
My answer: gcf=4
Find the lcm for each of the following groups of numbers which ever method you wish:8,15, and 20
My answer: Lcm=1
Find two factors of 15 with a difference of 2?
My answer: 3 and 5
Normally, we exclude 1 when listing lcm. In this case, it is wrong. The lcm is 120.
my question is are the other two answers correct or are they wrong as well.