1. We need to express numbers in scientific notation with 4 decimal places. 2. Scientific notation writes numbers as $a \times 10^b$, where $1 \leq |a| < 10$ and $b$ is an integer. 3. To round a number to 4 decimal places in scientific notation, first convert it, then round $a$ to 4 decimals. 4. Example: $12345 = 1.2345 \times 10^4$. 5. Example: $0.006789 = 6.7890 \times 10^{-3}$. 6. Always keep the format $a.aaaa \times 10^{b}$ with 4 decimals. 7. Please provide specific numbers for conversion if needed.