Final answer:
The number 12 belongs to the sets of natural numbers, whole numbers, integers, and real numbers.
Step-by-step explanation:
The number 12 belongs to the set of natural numbers, the set of whole numbers, the set of integers, and the set of real numbers.
Natural numbers are positive numbers that are used for counting, such as 1, 2, 3, etc. Whole numbers include zero as well, such as 0, 1, 2, 3, etc. Integers include positive and negative numbers, such as -3, -2, -1, 0, 1, 2, 3, etc. Real numbers include all the numbers on the number line, such as fractions, decimals, and irrational numbers.