Solve Vertical Addition: 872 + 9 Step-by-Step

To solve this problem, we'll follow these steps:

• Step 1: Add the ones place.
• Step 2: Handle any carrying to the tens place.
• Step 3: Add the tens place.
• Step 4: Handle any carrying to the hundreds place.
• Step 5: Add the hundreds place.

Now, let's work through each step:

Step 1: Consider the ones digits. For 872 and 9, the ones digits are 2 and 9.
Adding these gives us $2 + 9 = 11$.

Step 2: In base-10 addition, if the sum of digits in a place (in this case, the ones place) exceeds 9, we carry over to the next leftward digit. Thus, we write 1 in the ones place and carry over 1 to the tens place.

Step 3: Now, we add the tens digits. For the tens, we have 7 (from 872) and the 1 from our carry over.
Thus, $7 + 1 = 8$.

Step 4: After adding the tens digits, check if there's any carry over. Since 8 is not greater than 9, no further carrying is needed.

Step 5: Finally, add the hundreds place digits. For the hundreds, we have 8 (from 872), and there was no carry from the tens, giving $8 + 0 = 8$.

Combining these sum results, we have the final sum as: Hundreds: 8
Tens: 8
Ones: 1
Therefore, the sum of 872 and 9 is $881$.

Therefore, the solution to the problem is $881$.

The choice that corresponds to this solution is Choice 4: $881$.