1. **State the problem:** Calculate the sum of 1 and 4. 2. **Formula used:** Addition of two numbers is given by $a + b$. 3. **Apply the formula:** Here, $a = 1$ and $b = 4$, so we calculate $1 + 4$. 4. **Perform the addition:** $1 + 4 = 5$. 5. **Final answer:** The sum of 1 and 4 is **5**.