What Is Infinity in Math?

You cannot measure infinity.
••• Aeya/iStock/Getty Images

In math, infinity is a concept that refers to an endless quantity that's larger than every real number. The symbol for infinity resembles a sideways number eight. Students are introduced to the concept of infinity during or before middle school, but they usually don’t use infinity much until calculus.

What Infinity Is

Although infinity is larger than any number in existence, it is not a real number. Unlike real numbers in which you add two numbers to produce a larger number such as 2+5 = 7, if you add infinity + 1, you get infinity. If you add infinity to infinity, you will see that infinity + infinity = infinity. Infinity is not only enormous, it is also endless. You cannot measure infinity; add any quantity to infinity, and you will always get infinity.

Mathematical Examples

Although infinity isn’t widely applied before calculus, math has many examples of infinity. For example, the sequence of numbers -- 1, 2, 3 and so on -- extends infinitely. When you write certain fractions in decimal form, they will repeat infinitely. For example, a calculator will show that 2/3 equals 0.6666, but the row of sixes in the number 0.6666 doesn’t end after four digits. The sixes in the number 0.6666 continue as far as a calculator screen will allow; in theory, the number 0.6666 extends forever -- infinitely. In geometry, a line segment has two distinct endpoints – points A and B. A line, however, will extend infinitely in either direction.

Related Articles

What Is a Nonzero Number?
What Is the Difference Between Finite Math & Pre-Calculus?
Definition of Successor and Predecessor in Math
How to Read Log Scale Graphs
Is Majoring in Mathematics Worth It?
What Are Consecutive Fractions?
How to Calculate Antilog
How to Convert an Infinite Decimal to a Fraction
What is the Identity Property of Multiplication?
What Does E Mean in Math?
How to Calculate a Natural Logarithm
What are Imaginary Numbers?
Math Courses in College
What Are Math Computation Skills?
Basic Concepts in Mathematics
Algebra Rules for Beginners
What are Real Numbers?
How to Interpret Dreams With Numbers
A Description of Parallel & Perpendicular Lines
What Are the Applications of Discrete Math?