Solve Vertical Addition: 73 + 18 Step-by-Step

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

• Step 1: Align the numbers by place value, ensuring the units and tens are in the correct columns.
• Step 2: Add the digits in the units column (3 and 8).
• Step 3: Address any carryover from the units addition, which affects the tens column calculation.
• Step 4: Add the digits in the tens column (7 and 1), including any carry.

Now, let's work through each step:

Step 1: The problem provides the vertical alignment:
$\begin{array}{c} 73 \\ +18 \\ \end{array}$
We confirm that the units and tens digits are properly aligned.

Step 2: Add the units digits (3 and 8):
$3 + 8 = 11$
Place the 1 in the units position and carry over 1 to the tens position.

Step 3: Add the tens digits along with the carryover:
$7 + 1 + 1 = 9$
Write the 9 in the tens position for the sum.

The resulting sum of the numbers vertically added is:
$\begin{array}{cc} & 91 \\ \end{array}$
Therefore, the solution to the problem is $91$.