The World of Numbers Mind Map

The number system is a family of number sets arranged from counting numbers to all real numbers: natural numbers, whole numbers, integers, rational numbers, irrational numbers, and real numbers.

When asked to classify a number, place it in the smallest correct set first and then mention the larger sets it belongs to.

A rational number is any number that can be written as p/q, where p and q are integers and q is not zero.

For number-line questions, first locate the two nearest integers and then divide the interval according to the denominator.

An irrational number is a real number that cannot be written as p/q, where p and q are integers and q is not zero.

Check whether the number under the square root is a perfect square before deciding whether the square root is rational or irrational.