3/8 is already in its simplest form as a fraction. The numerator, 3, and denominator, 8, have no common factors other than 1. To simplify a fraction to its simplest form, you divide both the numerator and denominator by their greatest common factor (GCF). In this case, the GCF of 3 and 8 is 1, so there's no need to simplify further. Therefore 3/8 is already in its simplest form.