Rational - GCSE Maths Definition

In mathematics, a rational number is any number that can be written as a fraction. Integers, fractions (obviously!), terminating and recurring decimals are all rational numbers.

Another way of considering rational numbers is that, unlike irrational numbers, you would generally be able to place them in an exact position on a number line. Examples of rational numbers include

• (fraction) - on a number line with marks every quarter, this would be marked between and

• 5 (integer) - on a number line with marks every whole numbers, this would be marked between 4 and 6

• 1.333 333 ... (recurring decimal) - on a number line with marks every , this would be marked between 1 and

• 0.35 (terminating decimal) - on a number line with marks every 0.01, this would be marked between 0.34 and 0.35

Irrational numbers, such as 𝜋, cannot be marked exactly on a number line (well, not without some crafty mathematical thinking that goes beyond GCSE Mathematics!).