Real numbers are any number that you can think of, in other words, any number that is not imaginary. It includes whole numbers (like 0,1,2,3 etc.), fractions (like ½, ¼, ⅓ etc.), decimals (like 4.5, 5.6, 0.87 etc.), and even negative numbers (like -5, -7, -20 etc.) Real numbers are used to help us measure and count things in the world.