The set of rational numbers, represented by the symbol Q, is formed by all numbers that can be expressed as the ratio between two integers, ba, where b=0. -3,31,5,4531 All four of these examples are rational numbers. Note that integers are also rational, because they can always be written as fractions with a denominator of 1. -3=1-3,5=15 Real numbers which are not rational are called irrational numbers.