A gallon fraction is a unit of measurement used to describe the amount of liquid in a container. The term 'gallon fraction' is composed of three parts: pint, quart, and fifth. A pint is a unit of measurement equal to one-eighth of a gallon, or 16 fluid ounces. A quart is a unit of measurement equal to one-fourth of a gallon, or 32 fluid ounces. A fifth is a unit of measurement equal to one-fifth of a gallon, or 25.6 fluid ounces.