Let's match each expression with its correct scientific notation:
- .55 × 10^9 → 5.5 × 10^8
- 49 → 4.9 × 10^1
- 499 × 10^7 → 4.99 × 10^9
- 397.3 × 10^{-1} → 3.973 × 10^2
- 0.000236 → 2.36 × 10^{-4}
So the matches are:
- .55 × 10^9 → 5.5 × 10^8
- 49 → 4.9 × 10^1
- 499 × 10^7 → 4.99 × 10^9
- 397.3 × 10^{-1} → 3.973 × 10^2
- 0.000236 → 2.36 × 10^{-4}