`1.1 + 12.12 + 123.123 =` ?
A. 134.343
B. 133.433
C. 132.123
D.136.343

Options

A. C
B. D
C. B
D. A

Answer

To solve the problem \(1.1 + 12.12 + 123.123\), we will follow these steps:

### Step 1: Align the numbers
We will align the numbers by their decimal points for easier addition:

```
1.100
12.120
123.123
```

### Step 2: Add the numbers column-wise
Now, we will add the numbers starting from the rightmost column (the thousandths place):

1. **Thousandths place**: \(0 + 0 + 3 = 3\)
2. **Hundredths place**: \(0 + 2 + 2 = 4\)
3. **Tenths place**: \(1 + 1 + 1 = 3\)
4. **Units place**: \(1 + 2 + 3 = 6\)
5. **Tens place**: \(0 + 1 + 2 = 3\)
6. **Hundreds place**: \(0 + 0 + 1 = 1\)

### Step 3: Combine the results
Now, we will combine the results from each column:

```
136.343
```

### Final Answer
Thus, \(1.1 + 12.12 + 123.123 = 136.343\).

The correct option is **D. 136.343**.

---