What is the correct simplification of 243 3/5

To simplify \( 243 \frac{3}{5} \), we first convert the mixed number into an improper fraction.

1. **Convert the whole number to a fraction**:
- The whole number \( 243 \) can be expressed as \( \frac{243 \times 5}{5} = \frac{1215}{5} \).

2. **Add the fractional part**:
- Now, we add the fractional part \( \frac{3}{5} \):
\[
\frac{1215}{5} + \frac{3}{5} = \frac{1215 + 3}{5} = \frac{1218}{5}
\]

Thus, the correct simplification of \( 243 \frac{3}{5} \) is:
\[
\frac{1218}{5}
\]

If you're looking for a decimal conversion:
\[
\frac{1218}{5} = 243.6
\]

So, the final answers are \( \frac{1218}{5} \) or \( 243.6 \), depending on how you want it expressed.