One way to determine the number is to multiply 2 and 9, this is because the resulting number will be divisible by them perfectly. Let's try:
[tex]2\cdot9=18[/tex]So our candidate is 18, we need to test if it's divisible by 2 and 9 perfectly:
[tex]\begin{gathered} \frac{18}{2}=9 \\ \frac{18}{9}=2 \end{gathered}[/tex]It is, therefore the number is 18.
