Calculate the Sum: 728 + 56 in Vertical Format

$\begin{aligned} &728 \\ +& \\ &~~56 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

To solve this problem, we need to add the numbers 728 and 56 using vertical addition. Let's break this down step by step:

• Step 1: Add the ones place digits. Here, we add $8 + 6 = 14$. The digit 4 remains in the ones place, and we carry over the 1 to the tens place.
• Step 2: Add the tens place. Now, add the tens digits, taking into account the carry-over: $2 + 5 + 1 = 8$. Write 8 in the tens place.
• Step 3: Add the hundreds place. Since there are no more digits to add to the hundreds place and no carry over, we keep the hundreds digit as is: $7$.

Thus, the sum of 728 and 56 is $784$.

Therefore, the correct answer is choice 2: 784.