Which sequence describes how to multiply decimals?

• A. Multiply the numbers as if they were whole numbers, then place the decimal in the product according to the sum of decimal places.
• B. Align the decimal points and add the decimal places in the factors to determine the product's decimal places.
• C. Convert the decimals to fractions and multiply, then convert back to decimals.
• D. Multiply the decimals and round to the nearest tenth.

Answer: (A)

When you multiply decimals, treat them as if there were no decimal points and multiply the numbers as if they were integers. Then place the decimal in the product based on how many digits are to the right of the decimal in each factor.

The key rule is that the total number of decimal places in the product equals the sum of the decimal places in the two factors. This rule lets you place the decimal correctly every time, without guessing.

For example, 0.6 times 0.04: ignore decimals and multiply 6 by 4 to get 24. The first number has 1 decimal place and the second has 2, so the product should have 3 decimal places. Put the decimal to get 0.024.

This matches the described method: multiply as whole numbers, then use the sum of decimal places to determine where the decimal goes in the product.

Converting decimals to fractions and multiplying is another valid approach, but it follows a different route. Rounding to the nearest tenth would lose precision, so it isn’t appropriate for finding the exact product.