Solve the Addition Problem: 987 + 13 in Vertical Format

To solve this problem, we'll perform a vertical addition of two numbers:

• Step 1: Arrange the numbers vertically by their place value:

$\begin{aligned} & 987 \\ + & 13 \\ \hline \end{aligned}$

• Step 2: Add the digits in the ones place.

Add 7 (ones place of 987) to 3 (ones place of 13) to get 10. Since this sum is 10, we write down 0 in the ones place and carry over 1 to the tens place.

• Step 3: Add the digits in the tens place.

Add 8 (tens place of 987) to 1 (tens place of carry-over) + 1 (tens place of 13). This is 8 + 1 + 1 = 10. We write 0 in the tens place and carry over 1 to the hundreds place.

• Step 4: Add the digits in the hundreds place.

Add 9 (hundreds place of 987) to 1 (carry-over). This sum is 9 + 1 = 10. We write 0 in the hundreds place and carry over 1 to the next higher place, the thousands place.

• Step 5: Combine the result.

Since the only carried-over is 1 to the thousands place, we write it as is. So the result of the addition is 1000.

Therefore, the solution to this problem is $1000$.