To find out how much farther Neptune is from Earth than Mars, we need to subtract the distance from Earth to Mars from the distance from Earth to Neptune.
Given:
- Distance from Earth to Mars = \( 2.25 \times 10^8 \) km
- Distance from Earth to Neptune = \( 4.3514 \times 10^9 \) km
Now, we perform the subtraction:
\[ 4.3514 \times 10^9 \text{ km} - 2.25 \times 10^8 \text{ km} \]
To subtract these numbers effectively, we should express \( 2.25 \times 10^8 \) in the same power of ten as \( 4.3514 \times 10^9 \). We can do this by rewriting it as:
\[ 2.25 \times 10^8 = 0.225 \times 10^9 \]
Now we can subtract:
\[ 4.3514 \times 10^9 - 0.225 \times 10^9 = (4.3514 - 0.225) \times 10^9 \]
Now calculate the subtraction:
\[ 4.3514 - 0.225 = 4.1264 \]
So, we have:
\[ 4.1264 \times 10^9 \]
The distance from Earth to Neptune is \( 4.1264 \times 10^9 \) km farther than the distance from Earth to Mars. Thus, the final answer, expressed in scientific notation, is:
\[ \boxed{4.1264 \times 10^9} \text{ km} \]