The <em>correct answer</em> is:
You fill in the missing spaces with zeros.
Explanation:
When we multiply decimals, we multiply the digits the same way we would whole numbers. When we get the product, we count the number of digits in the problem that are behind a decimal point; this will be the number of decimal places in the answer. If we do not have enough spaces, we replace them with zeros.
For instance, if we multiply two numbers that are each in the hundredths place, we will have 2+2 = 4 decimal numbers in our answer. If our answer gives us only 3 digits, we place a zero in front and then place the decimal.