13. Express 0.9% as a decimal.

Answer: A

Explanation:

0.9% as a decimal is 0.009.

To convert a percentage to a decimal, divide the percentage by 100. Thus, 0.9% equals 0.9 divided by 100, which equals 0.009.

A) 0.009

This option is correct as it accurately represents the decimal form of 0.9% obtained by dividing 0.9 by 100.

B) 90

This option is incorrect. A percentage value of 0.9% does not convert to 90; rather, it indicates a much smaller quantity when expressed as a decimal.

C) 9

This option is also incorrect. The value of 9 does not correspond to 0.9% in decimal form, which should be significantly less than 1.

D) 0.09

This option is incorrect as well. While 0.09 is a decimal, it represents 9%, not 0.9%, thus misrepresenting the original percentage.

Conclusion

The correct answer is A) 0.009, as it accurately reflects the conversion of 0.9% into decimal form. All other options misinterpret the percentage, either by presenting values that are too high or that represent different percentages altogether.