1. **State the problem:** Calculate the sum of 100 and 300.
2. **Formula used:** Addition of two numbers is given by $a + b$.
3. **Apply the formula:** Here, $a = 100$ and $b = 300$, so we calculate:
$$100 + 300$$
4. **Perform the addition:**
$$100 + 300 = 400$$
5. **Final answer:** The sum of 100 and 300 is 400.
Simple Addition 5748A7
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.