1. The problem is to find the sum of 620 and 1000. 2. The formula for addition is $a + b = c$, where $a$ and $b$ are the numbers to add, and $c$ is the result. 3. Substitute the values: $620 + 1000$. 4. Add the numbers: $620 + 1000 = 1620$. 5. Therefore, the sum of 620 and 1000 is $1620$.