Answer :
[tex]20|2 \\ 10|2 \\ 5 \ |5 \\ 1 \\\\\boxed{ 5} \ it's \ a \ multiple \ of \ 20 , \ but \ it's \ not \ a \ multiple \ of \ 2[/tex]
5 and 1 because multiples of 2:2,4,10 those are also factors of 20.Factors of 20: 1, 2, 4, 5, 10
