 The real numbers include all the rational numbers, such as the integer −5 and the fraction 4/3, and all the irrational numbers, such as (1.41421356..., the square root of 2, an irrational algebraic number).Included within the irrationals are the transcendental numbers, such as (3.14159265...).In addition to measuring distance, real numbers can be used to measure quantities such as time, mass, energy, velocity, and many more.