Which term refers to the union of both rational and irrational numbers?

The term that refers to the union of both rational and irrational numbers is "real numbers." Real numbers encompass a broad range of values, including all the numbers that can be found on the number line. This includes rational numbers, which can be expressed as fractions or ratios (such as 1/2 and -3), and irrational numbers, which cannot be expressed as a simple fraction (like the square root of 2 or the number π).

The other options each represent different sets of numbers. Whole numbers include all the non-negative integers but do not incorporate fractions or irrational numbers. Integers consist of all whole numbers, both positive and negative, but exclude fractions and irrational numbers. Natural numbers are the set of positive counting numbers (1, 2, 3, etc.) and do not include zero, negative numbers, or any fractions or irrationals. This distinction makes "real numbers" the only term that accurately captures the full range of both rational and irrational numbers.