Here are the expressions matched with their correct Scientific Notation:
- 49 - 4.9 × 10^1
- 499 × 10^7 - 4.99 × 10^9
- 397.3 × 10^−1 - 3.973 × 10^2
- 0.55 × 10^9 - 5.5 × 10^8
- 0.000236 - 2.36 × 10^−4
If you need further assistance or a specific format, let me know!