How do you know if a number is rational or irrational

A rational number is a number that is not repeating. So a rational number can be 5 or 2.3314. But Pi is irrational. So is 1/3 and 2/3 because in decimal form they are repeating. Which means they will go on forever which makes them irrational.

A rational number is, as the name implies, any number that can be expressed as a ratio, or fraction.An irrational number can be written as a decimal, but not as a fraction.

your answer would be 12