Correct Answer: A

Rationale: To convert 0.004 to a ratio, we can express it as 4/1000, which simplifies to 1/250. Therefore, the correct ratio is 1:250. Choice B (4:200) is incorrect as it simplifies to 1:50, not 1:250. Choice C (2:400) simplifies to 1:200, which is also incorrect. Choice D (9:200) simplifies to a ratio greater than 1:1, which is not equivalent to 1:250.

Correct Answer: B

Rationale: The correct answer is B: 2 liters. To convert milliliters to liters, you need to divide by 1000 since there are 1000 milliliters in a liter. Therefore, 2,000 milliliters is equal to 2 liters (2000 · 1000 = 2). Choices A, C, and D are incorrect because they incorrectly convert milliliters to liters, resulting in values that are too low (A and C) or too high (D).

Correct Answer: B

Rationale: The decimal 0.2 is already at the nearest tenth, so it does not need to be rounded. Rounding to the nearest tenth means keeping one decimal place, which is already the case with 0.2. Therefore, the correct answer is 0.2, as it is already at the specified rounding point. Choices A, C, and D are incorrect because they represent values that are not the result of rounding 0.2 to the nearest tenth. 0.1 is rounding down, 0.3 is rounding up, and 0.25 is not the nearest tenth of 0.2.

Correct Answer: C

Rationale: To convert liters to milliliters, you need to multiply the number of liters by 1,000 because there are 1,000 milliliters in a liter. Therefore, 0.1 liter is equal to 100 milliliters. Choice A (1 ml) is incorrect because it represents the conversion of 0.01 liters, not 0.1 liters. Choice B (10 ml) is incorrect as it also represents the conversion of 0.01 liters. Choice D (1000 ml) is incorrect as it represents the conversion of 1 liter, not 0.1 liter.

Correct Answer: B

Rationale: The correct answer is B: '10 mm'. There are 10 millimeters in 1 centimeter. To convert centimeters to millimeters, you multiply by 10 because 1 centimeter is equivalent to 10 millimeters. Choice A '1 mm' is incorrect as it represents the size of 1 millimeter, not the conversion from centimeters to millimeters. Choice C '100 mm' is incorrect as it is the equivalent of 1 meter, not 1 centimeter. Choice D '1,000 mm' is incorrect as it is the equivalent of 1 meter, not 1 centimeter.