Solve Vertical Addition: 423 + 55 Step-by-Step

$\begin{aligned} &423 \\ +& \\ &~~55 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

To solve this addition problem, follow these steps:

• Step 1: Add the digits in the units place: $3 + 5 = 8$. Write down 8 in the units place.
• Step 2: Add the digits in the tens place: $2 + 5 = 7$. Write down 7 in the tens place. No carrying is needed.
• Step 3: Add the digits in the hundreds place: $4 + 0 = 4$. Write down 4 in the hundreds place.

After performing these steps, the final sum is:

$\begin{aligned} &423 \\ +& \\ &~~55 \\ \hline &478 \\ \end{aligned}$

Therefore, the sum of 423 and 55 is $478$.