1. The problem is to understand what a natural number is. 2. Natural numbers are the set of positive integers starting from 1 and going upwards: $1, 2, 3, 4, 5, \dots$ 3. They are used for counting and ordering. 4. Sometimes, natural numbers are defined to include zero, i.e., $0, 1, 2, 3, \dots$ depending on the context. 5. They do not include fractions, decimals, or negative numbers. 6. Hence, natural numbers are simply whole, positive numbers starting at 1 or 0 depending on the definition used.