Question

Is $25$ a multiple of $2$ or $5$? How do you know?

Answer 1

$25$ is a multiple of $5$
Also any multiple of $2$ would be even but $25$ is odd so $2$ can not be a factor of $25$
Simply list out the multiples of $2$ and $5$ first
Multiples of $5$ include: $5.10,15,20,25,30,35$
Multiples of $2$ include: $2,4,6,8,10,12,14,16,18,20,22,24,26$ and etc
the multiples of $2$ skip the number $25$ so we can immediately assume that $25$ is not a multiple of $2$. Therefore it must be a multiple of $5$
$5+5+5+5+5=25$
$5^2=25$
$5\times 5=25$