Correct Answer: A

Rationale:
To convert liters to milliliters, you need to multiply by 1000 because 1 liter is equal to 1000 milliliters.
Therefore, when you convert 0.5 liters to milliliters, you get 500 milliliters (0.5 * 1000 = 500). This conversion is commonly used in various situations where different units of volume are required.

Choices B, C, and D are incorrect because they do not follow the correct conversion factor between liters and milliliters.

Correct Answer: A

Rationale:
To convert kilograms to grams, you need to multiply by 1,000 since there are 1,000 grams in a kilogram.
Therefore, 0.1 kg equals 100 grams.
Choice B (10 g) is incorrect because it represents converting 0.01 kg to grams.
Choice C (1 g) is incorrect as it reflects the conversion of 0.001 kg to grams.
Choice D (0.1 g) is the value in grams equivalent to 0.01 kg, not 0.1 kg.

Correct Answer: B

Rationale:
To convert grams to milligrams, you need to multiply by 1,000 because there are 1,000 milligrams in 1 gram.
Therefore, 1 gram 1,000 = 1,000 milligrams.
Choice A (100 mg) is incorrect as it represents 0.1 grams, not 1 gram.
Choice C (1 mg) is incorrect as it represents a fraction of a gram.
Choice D (10,000 mg) is incorrect as it is 10 times more than the correct conversion.

Correct Answer: A

Rationale:
To convert liters to quarts, we know that 1 liter is approximately equal to 1.06 quarts.
Therefore, 2 liters would be around 2.12 quarts. However, for practical purposes, it's often rounded to 2.1 quarts. Option A, '1.06 quarts,' is the closest and most accurate approximation. Option B, '0.5 quarts,' is incorrect as it represents half of the actual conversion. Option C, '2.1 quarts,' is close but slightly higher than the actual conversion. Option D, '4 quarts,' is double the correct conversion and is therefore incorrect.

Correct Answer: B

Rationale: The calculation of 0.4 divided by 40 results in 0.01, which can be expressed as 1/100. This fraction is the correct representation of the division of 0.4 by 40.
Choice A, 1/100, is the correct answer as it accurately reflects the division.

Choices C and D, 1/400 and 1/40000 respectively, do not correctly represent the division operation performed on 0.4 and 40, leading to incorrect results and are therefore not the correct answers.