How would you classify the number 0.333...?

The number 0.333... represents a repeating decimal, which can be expressed as a fraction. In this case, 0.333... is equivalent to 1/3. Any number that can be represented as a fraction, where both the numerator and the denominator are integers (with the denominator not equal to zero), is classified as a rational number.

Rational numbers include all integers, whole numbers, and their opposites, as well as fractions and repeating or terminating decimals. Since 0.333... can be converted to the fraction 1/3, it fits within the definition of a rational number, thus making this classification correct.

In contrast, irrational numbers cannot be expressed as the ratio of two integers and are represented by non-repeating, non-terminating decimals, such as the square root of 2 or pi. Whole numbers are non-negative integers starting from zero, while natural numbers typically refer to the set of positive integers (1, 2, 3, etc.), so 0.333... does not fit those classifications either.