Working with measurements often requires converting from one unit of measurement to another. You may need to covert feet to miles or ounces to gallons in the U.S. customary measurement system, or centimeters to meters or milligrams to grams in the metric system. These sorts of calculations use fractions and mixed numbers to describe quantities, so you’ll need be familiar with performing operations on them. While you are studying mixed numbers and fractions, it will be a good opportunity for you to gain experience simplifying other kinds of expressions containing fraction bars and complex fractions (fractions containing fractions).