A rational number is a number that can be expressed as a fraction of two integers, a/b, where a and b are integers and b is not equal to zero. For instance, the number 1/2 is a rational number because it can be expressed as a fraction of the integers 1 and 2.
Rational numbers are important in mathematics because they represent all numbers that can be represented as fractions. This makes them useful for many applications, such as measuring lengths, counting objects, and solving equations. Historically, the development of rational numbers was a major advance in mathematics.
