How much less is `28.8` km than `42.3` km?

Options

A. `13.5` km
B. `11.5` km
C. `13` km
D. none of these

Answer

To find out how much less `28.8` km is than `42.3` km, we need to subtract `28.8` from `42.3`. Here’s how to do it step by step:

### Step 1: Write the numbers in a column for subtraction.
```
42.3
- 28.8
```

### Step 2: Align the decimal points.
Make sure that the decimal points are lined up vertically. This helps in subtracting the numbers correctly.

### Step 3: Subtract the numbers starting from the rightmost side.
- Start with the hundredths place: `0.3 - 0.8`. Since we cannot subtract `8` from `3`, we need to borrow `1` from the tenths place.
- After borrowing, the tenths place becomes `1` (from `2`), and the hundredths place becomes `10`. Now we can subtract: `10 - 8 = 2`.

### Step 4: Move to the tenths place.
- Now we have `1` (after borrowing) in the tenths place. So, we subtract: `1 - 8`. Again, we cannot subtract `8` from `1`, so we borrow `1` from the units place.
- The units place `4` becomes `3`, and the tenths place becomes `11`. Now we can subtract: `11 - 8 = 3`.

### Step 5: Move to the units place.
- Now we have `3` in the units place (after borrowing). We subtract: `3 - 2 = 1`.

### Step 6: Combine the results.
Putting it all together, we have:
```
42.3
- 28.8
-------
13.5
```
Thus, `28.8` km is `13.5` km less than `42.3` km.

### Final Answer:
`28.8` km is `13.5` km less than `42.3` km.

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