Calculate the Sum: Solving 10.1 + 2.3 Step by Step

To solve this problem, we will perform the following steps:

• Step 1: Align the decimal numbers so the decimal points are vertically in line. The numbers are $10.1$ and $2.3$.
• Step 2: Add the numbers starting from the rightmost column (i.e., the tenths place), moving to the left.

Let's perform the addition:

$\begin{array}{c} 10.1 \\ + 2.3 \\ \hline \end{array}$

Starting from the right, we add the digits in the tenths place: $1 + 3 = 4$.

Next, add the digits in the units place: $0 + 2 = 2$.

Finally, add the digit in the tens place: $1 + 0 = 1$.

Therefore, the result of adding $10.1 + 2.3$ is:

$12.4$

We can verify that this matches with the given answer choices. The correct choice is:

Option 1: $12.4$