Which is a correct example of scientific notation?

• A. 6.5 × 10^8
• B. 65 × 10^6
• C. 0.65 × 10^9
• D. 6.5 × 10^-8

Answer: (A)

In scientific notation, a number is written as a × 10^n where a is between 1 and 10 and n is an integer. This format helps keep numbers compact and easy to compare. The first option fits this rule perfectly: the coefficient 6.5 lies between 1 and 10 and the exponent 8 is an integer, so it is a correct and standard example of scientific notation. The second option uses a coefficient of 65, which is outside the 1–10 range, so it isn’t in standard scientific notation unless you rewrite it (as 6.5 × 10^7). The third option uses a coefficient of 0.65, which is less than 1, so it isn’t in standard form without moving the decimal point (as 6.5 × 10^8). The last option does have a valid coefficient and an integer exponent, so it also represents scientific notation, but the first option is the clearest, textbook example.