Fractions represent parts of a whole. A fraction has two numbers separated by a line, with the number on top called the numerator and the bottom number called the denominator. Fractions can be equivalent if their lowest terms are the same, like if they represent the same part of the whole. Fractions are either proper if the numerator is less than the denominator, or improper if the numerator is greater than or equal to the denominator. Mixed numbers contain both an integer and an improper fraction.