irrational number
compound.a number that cannot be written as a simple fraction because its decimals go on forever without repeating a pattern.
compound.a real number that cannot be expressed as a ratio of two integers. Its decimal expansion is non-terminating and non-recurring.
“Pi is the most famous irrational number.”
“In math class, we learned that the square root of two is an irrational number.”
“The discovery of irrational numbers challenged the ancient Pythagorean belief that all things in the universe could be measured by whole numbers and their ratios.”
primarily used in mathematical and scientific contexts.
contrast with 'rational number' (which can be a fraction); use the number Pi as a concrete anchor for students to visualize the infinite, non-repeating decimal.