Solve Vertical Addition: 25 + 6 Step-by-Step

To solve this problem, let's calculate the sum of the numbers 25 and 6 using vertical addition:

Step 1: Align the numbers in vertical format.
The tens and ones are aligned as follows:

• Tens place: $2$

• Ones place: $5$

• $+$ $6$ (ones place)

• $\underline{\phantom{52}}$

Step 2: Add the digits in the ones place.
$(5 + 6 = 11)$. Since the sum exceeds 9, write down $1$ in the ones place and carry over $1$ to the tens place.

Step 3: Add the digits in the tens place, considering the carryover.
$(2 + 1 = 3)$.

Thus, the complete sum is $31$.

Therefore, the sum of 25 and 6 is $\mathbf{31}$, making choice 2 the correct one.