Solve Vertical Addition: 99 + 25 Step-by-Step

$\begin{aligned} &99 \\ +& \\ &25 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

To solve this problem, we'll perform vertical addition for the numbers 99 and 25:

• Step 1: Add the ones place digits:
  The ones digit of 99 is 9, and the ones digit of 25 is 5. Adding these together: $9 + 5 = 14$. We write down 4 and carry over the 1.
• Step 2: Add the tens place digits, including the carryover:
  The tens digit of 99 is 9, and the tens digit of 25 is 2. With the 1 carried over, we compute: $9 + 2 + 1 = 12$. Since there's no place to the left of tens for a third digit in this case, the whole number 12 is written in the tens and hundreds place.

Combining these, the sum is put together as 124.

Therefore, the solution to the problem is $124$.