Which option is the correct scientific notation for 4,000,000?

• A. 4 × 10^5
• B. 4 × 10^7
• C. 4 × 10^6
• D. 40 × 10^4

Answer: (C)

In scientific notation, you express a number as a coefficient between 1 and 10 multiplied by a power of 10. For 4,000,000, move the decimal six places to the left to get 4.0, and the number of places moved becomes the exponent, giving 4 × 10^6. That matches 4,000,000 exactly.

The other forms would produce different values: 4 × 10^5 equals 400,000, and 4 × 10^7 equals 40,000,000. The form 40 × 10^4 isn’t standard scientific notation, since the coefficient should be between 1 and 10; it would be rewritten as 4 × 10^5.