Correct Answer: A

Rationale: To multiply decimals, align the numbers as whole numbers, multiply as if they were whole numbers, then adjust the decimal point in the final answer. When multiplying 0.67 by 0.09, the result is 0.0603. To get this result, multiply 67 by 9 to get 603, then adjust the decimal point two places to the left in the final product, resulting in 0.0603. Choice B, 0.6, is incorrect because it does not account for the decimal precision in the multiplication. Choice C, 0.603, is incorrect as it has the digits reversed when compared to the correct answer. Choice D, 0.06, is incorrect as it does not reflect the correct product of the two decimals being multiplied.

Correct Answer: B

Rationale: The correct answer is 12,541.8. To find this result, you multiply 226 by 55.3, which equals 12,541.8. Choices A, C, and D are incorrect because they do not reflect the accurate multiplication of 226 by 55.3.

Correct Answer: A

Rationale: Let the width of the rectangle be x cm, and its length be 2x cm. The area of the rectangle is 2x * x = 2x², and the area of the square is 12² = 144 cm². Setting the areas equal gives 2x² = 144. Solving for x gives x = 6. Thus, the width is 6 cm, and the length is 12 cm. The perimeter is 2(6 + 12) = 36 cm. Therefore, the correct answer is 36 cm. Choice B, 46 cm, is incorrect because it does not match the calculated perimeter. Choices C and D are also incorrect as they do not reflect the correct calculation of the rectangle's perimeter.

Correct Answer: A

Rationale: The correct answer is A: 3000 meters. To convert kilometers to meters, you need to know that there are 1000 meters in 1 kilometer. Therefore, to find the number of meters in 3 kilometers, you multiply 3 by 1000, resulting in 3000 meters. Choice B, 2000 meters, is incorrect as it doesn't account for the correct conversion factor. Choice C, 3500 meters, and Choice D, 2500 meters, are also incorrect as they provide inaccurate conversions.

Correct Answer: A

Rationale: The correct answer is A: 4000 grams. To convert kilograms to grams, you need to multiply the number of kilograms by 1000 since there are 1000 grams in 1 kilogram. Therefore, 4 kilograms is equal to 4 x 1000 = 4000 grams. Choice B (3000 grams), C (4500 grams), and D (3500 grams) are incorrect as they do not correctly convert 4 kilograms into grams.