1. **State the problem:** Calculate the sum of 7 and an unknown number represented by a blank. 2. **Formula used:** Addition is the operation of combining two numbers to get their total. 3. **Intermediate work:** Since the second number is missing, the expression is incomplete. If the problem is simply to add 7 to another number, the result depends on that number. 4. **Explanation:** To solve an addition problem, you add the values of the two numbers. Here, since the second number is not provided, the sum cannot be determined. 5. **Final answer:** The expression is incomplete; please provide the second number to calculate the sum.