One number is five more than another. The sum of the two numbers is twenty-one. What are the two numbers?

1. Let n represent the first number, so n plus 5 represents the second number, which is five more. 2. The sum of the two numbers is twenty-one: n plus (n plus 5) equals 21. 3. Combine like terms: 2n plus 5 equals 21. 4. Subtract 5 and then divide by 2: 2n equals 16, so n equals 8. 5. The second number is n plus 5, which is 8 plus 5, or 13, so the numbers are 8 and 13. 6. Choosing 7 and 12 keeps the five-more relationship but their sum is only 19, not 21, so that pair fails the second condition. 7. Choosing 9 and 14 also differs by five, but 9 plus 14 equals 23, overshooting the required sum of 21. _Source: OpenStax Prealgebra (CC BY 4.0), Ch 9 "Math Models and Geometry", section 9.1 Use a Problem Solving Strategy_