if you're talking about the fraction 5/18, then yes, it is in simplest form.
It is already in its simplest form
It is already in its simplest form
It is already in its simplest form
It is already in its simplest form
It is already in its simplest form
The fraction 7/20 is already in its simplest form.
1/23 is already in its simplest form
7 over 100 is already in the simplest form.
already is in simplest form
its already in simplest form
Integers are already in their simplest form.
It is already in simplest form.