Answer: The number 28 belongs to several sets,
Step-by-step explanation: including:
1. The set of natural numbers: {1, 2, 3, ...}
2. The set of whole numbers: {0, 1, 2, 3, ...}
3. The set of integers: {..., -3, -2, -1, 0, 1, 2, 3, ...}
4. The set of rational numbers: numbers that can be expressed as a fraction (e.g., 28/1, 56/2, -28/1).
5. The set of real numbers: numbers that can be represented on a number line (includes fractions, decimals, and irrational numbers like √2 and π).
6. The set of even numbers: {2, 4, 6, 8, ...}
7. The set of composite numbers: numbers that have factors other than 1 and themselves (e.g., 2, 4, 7, 14).
8. The set of abundant numbers: numbers for which the sum of their proper divisors is greater than the number itself (e.g., 12, 18, 20).
9. The set of multiples of 28: {28, 56, 84, 112, ...}.
10. The set of years in a calendar (e.g., 28 AD, 1928, 2128).