Whole numbers are the set of numbers that include zero and all positive integers. In other words, whole numbers are the numbers you count with—starting from zero—without any fractions or decimals.
Whole numbers are used to count objects, represent quantities, and perform basic arithmetic. They are a foundational concept in mathematics and appear in nearly every area, from everyday counting to computer science.
Here’s what they look like in set notation and on a number line.
{0, 1, 2, 3, 4, . . ., ∞}
It’s important to note that whole numbers do not include negative numbers or any parts of numbers (like 2.5 or ¾). This makes them different from integers, which do include negative values, and from rational numbers, which include fractions and decimals.
Whole numbers include all natural numbers plus zero, as shown in the Venn diagram below. Whole numbers add zero. Zero is a more advanced concept that mathematicians added to number theory relatively recently.
For example, if you have 4 apples, 0 books, or 15 students in a class, those quantities are all expressed using whole numbers.
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