Which concept is often used to simplify fractions?

Finding the Greatest Common Factor (GCF) is the correct choice for simplifying fractions because this method directly targets the highest number that can evenly divide both the numerator and the denominator of a fraction. By identifying the GCF, one can divide both parts of the fraction by this common factor, effectively reducing the fraction to its simplest form. This is a fundamental process in fraction simplification, as it maintains the equivalence of the fraction while making it easier to work with or interpret.

On the other hand, the other options do not directly relate to the process of simplifying fractions. Using exponents involves operations with powers, which can be significant in other mathematical contexts but does not pertain to simplifying fractions. Decimal conversion is about changing the form of a fraction rather than simplification, and multiplication does not serve the purpose of reducing fractions but rather increases their values unless it's by fractions that simplify after multiplication, which is not a general simplification process. Thus, focusing on the GCF is the most relevant and effective method for simplifying fractions.