Simplest Form (Lowest Terms)

Is this fraction in lowest terms 2/10 ?

8/12is in simplest form

18/45 is in simplest form.

Is 15/23 is simplest form?

Is 6/25 in simplest form?

14/21 is in simplest form.

18/63 is in simplest form.

Is 4/9 in simplest form?

15/20 is in lowest terms.

54/63 is in simplest form.