Explain what it means to express a fraction in simplest form

The simplest form of a fraction is when the top and bottom cannot be any smaller.

In simplest form means to find the greatest common factor that can go into both the numerator and denominator.

Example:

20/10 simplified to 2/1 or 2

This fraction can be simplified by 10 because 10 goes into both the numerator and denominator. 5 also goes into both, but the greatest common factor is 10.