Fractions can be divided into several groups. The most commonly used fractions are those with values between zero and one. These fractions are called proper fractions. Fractions equal to one are called unit fractions (for example, 4/4). Fractions with values greater than one are called improper fractions. Improper fractions can also be written as mixed numbers, as a whole number and a proper fraction.
A common way to determine if a fraction is proper or improper is to consider whether the numerator or denominator is the larger number. A proper fraction will be "larger" on the bottom -- an improper fraction will be "larger" on the top.