Solve Addition Problem: 917 + 73 in Vertical Format

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

• Align the numbers by place value.
• Add the numbers starting from the rightmost column, with carrying where necessary.
• Verify the results match one of the provided multiple-choice answers.

We can begin with the addition:

$\begin{aligned} &\phantom{+}917 \\ + &\phantom{9}~~73 \\ &\underline{\phantom{777}} \end{aligned}$

Let's add each digit column by column:

Step 1: Add the units place (rightmost column).

The units are 7 and 3. Add these together: $7 + 3 = 10$. Since 10 is more than 9, we place the 0 in the units place and carry over the 1 to the tens column.

Step 2: Add the tens place, including the carry from the previous step.

Now add the tens digits: $1 + 1 + 7 = 9$. (The 1 is carried from the previous step, and 9 is the result.) Place 9 in the tens column.

Step 3: Add the hundreds place.

The hundreds place has a 9 with nothing to add, so it remains 9.

The resulting sum from the addition is 990. Therefore, the correct answer is:

$990$

Verifying with the given multiple-choice options, the correct answer is choice 3.