Math Basics

All About Numbers

What are rational, irrational, and real numbers?

Rational, or fractional, numbers are most often regarded as divisions (or ratios) of integers. By creating a fraction (dividing one integer by another), a rational number produces either a number that “ends” or repeats decimals. For example, 1/4 equals the decimal equivalent of 0.25; 1/3 is equivalent to 0.33333 … Both of these are rational numbers. (For more information about fractions, see below.)

On the other hand, irrational numbers are all the numbers that can be written as non-repeating, non-finite (or non-terminating) decimals. Also called non-rational numbers, they include the decimal equivalent of pi (or 3.141592 …). Finally, if you put the rational and irrational numbers together, they form the real numbers. Most numbers we use in our everyday lives are real numbers.


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