Answer:
A variable represents a concept or an item whose magnitude can be represented by a number, i.e. measured quantitatively. Variables are called variables because they vary, i.e. they can have a variety of values. Thus a variable can be considered as a quantity which assumes a variety of values in a particular problem.
In mathematics, a variable is a symbol used to represent an arbitrary element of a set. In addition to numbers, variables are commonly used to represent vectors, matrices and functions.
The letters that represent variables and numbers are usually lowercase: a, b, c, and so on. Capitalized letters are used most commonly to represent the answer in a formula; for example, the capital A for area of a circle equals pi times the radius squared, A = πr².
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