How do you simplify 1/8

You can't. 1/8 is the simplest form.

Step 1: Factor both the numerator and denominator down to prime factors:1 cannot be prime factorized. Step 2: Calculate the greatest common factor, GCF (also called greatest common divisor, GCD), by taking all the common prime factors of the numerator and denominator, by the lowest powers.  Fraction's numerator and denominator are coprime numbers (no common prime factors), so the fraction cannot be reduced (simplified)