A fraction represents a part of a whole. A fraction consists of a top number that represents how many parts, and a bottom number that represents the total number of parts. For example, if a pizza is divided into 8 slices, and you eat 3 slices, you can say that you ate 3 eighths of the pizza, written as ⅜.

A decimal consists of a whole and a fractional part, separated by a decimal point. The fractional part is written as a sequence of digits, with the leftmost digit representing how many tenths of a whole number, the next digit representing how many hundredths, etc. For example, 0.5 is 5 tenths. If a pizza is divided into 10 slices, and you eat 5 slices, you can say that you ate 0.5 pizzas, or half the pizza.

Both fractions and decimals are ways to represent non-whole numbers. Sometimes it's easier to work with a decimal, so it can be useful to convert a fraction to a decimal. To convert, divide the top number, called the numerator, by the bottom number, called the denominator. For example:

numerator   = 1
denominator = 2
decimal     = 1 ÷ 2 = 0.5

Another example:

numerator   = 1
denominator = 3
decimal     = 1 ÷ 3 = 0.3

The bar over the 3 means the 3 repeats forever. This is called a repeating decimal. Sometimes a fraction converts to a repeating decimal due to the division process.