To solve problems about spans of time that include B.C. and A.D. dates, you would need to use which numbers? \( \begin{array}{ll}\text { A Integers } \\ \text { O } & \text { D irrational numbers }\end{array} \)

To solve problems involving spans of time that include B.C. (Before Christ) and A.D. (Anno Domini) dates, you need to use **integers**. Here's why: - **Integers** include both positive and negative whole numbers. In the context of historical dates: - **A.D. dates** are represented by positive integers (e.g., 2023 A.D.). - **B.C. dates** are represented by negative integers (e.g., 500 B.C. would be -500). Using integers allows you to perform arithmetic operations across the BC and AD divide seamlessly. For example, calculating the span between 500 B.C. (-500) and 300 A.D. (+300) involves integer addition: \[ -500 \text{ (B.C.)} + 300 \text{ (A.D.)} = 800 \text{ years} \] This approach simplifies the process of calculating time spans that cross from B.C. to A.D. **Answer:** A. Integers