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Variables

# Variables

An unknown quantity can be represented by a variable

Lesson Demo

An unknown quantity can be represented by a variable.  Usually, a variable is any letter from the English alphabet that represents an unknown quantity.  The relation between the unknown quantity and other quantities can be expressed with the help of the variable.  The value of the variable varies with the given condition on the variable.  A quantity whose value does not vary is called a constant.   An expression consisting of variables, constants and mathematical operators is called an algebraic expression.
Mathematical operations such as addition, subtraction, multiplication and division can be easily performed on variables.  We can use variables to form expressions based on patterns.

The following are some branches of mathematics:

• The branch of mathematics where letters are used along with numbers is called algebra.
• The branch of mathematics that deals with numbers, operations on numbers and properties of numbers is called arithmetic.
• The branch of mathematics that deals with the figures and shapes is called geometry.