Article

# Variables, Data Types, and Mathematical Operators

## Use this article as a reference sheet for JavaScript variables, data types, and mathematical operators.

Use this article as a reference sheet for JavaScript variables, data types, and mathematical operators.

• Variables — The `var` keyword indicates the creation of a variable.
• Data Types — `'New York City'` is a string, `40.7` is a number, and `true` is a boolean.
• Mathematical Operators — The addition (`+`), subtraction (`-`), multiplication (`*`), and division (`/`) characters function as mathematical operators.
``````var location = 'New York City';
var latitude = 40.7;
var inNorthernHemisphere = true;``````

Each line in the example above begins with the keyword `var`. The `var` keyword is used to create a variable. The word that immediately follows `var` is the name of the variable. The variable’s name should describe the value that it stores (e.g. `location`).

Variables can store any data type, including:

• String — Any grouping of keyboard characters (letters, spaces, numbers, or symbols) surrounded by single quotes (`'Hello'`) or double quotes (`"World!"`). In the example above, the string `'New York City'` is saved to the variable `location`.
• Number — Any number, including numbers with decimals: `4`, `1516`, `.002`, `23.42`. In the example above, the number `40.7` is saved to the variable `latitude`.
• Boolean — Either `true` or `false`, with no quotations. In the example above, the variable `inNorthernHemisphere` is set to `true`. The sample code below contains examples of mathematical expressions:
``````var num1 = 4;
var num2 = 9;
In the example above, the values saved to the variables were calculated using the addition (`+`), subtraction (`-`), multiplication (`*`), and division (`/`) operators.
Variables always store the final value of the expression on the right side of the equals sign (`=`).