According to the positioning rules of decimal multiplication product, it is understandable that the product should have two decimal places, and its product is 16.40, so it is correct; However, according to the basic nature of decimals, the 0 at the end of decimals can be omitted, so there is actually a decimal place.

According to the above situation, I personally think this question can be right or wrong. But because the word "must" is added to the question, if I have to give you a positive answer, I personally think it should be judged as "wrong". Generally speaking, questioners will not ask controversial questions (yes or no questions). Unless he comes with some purpose.

If there is such a problem in the actual exam, students can give reasons, and the reasons are sufficient. I think it's okay. Because the students' answers have gone far beyond the purpose of solving this problem.

The above opinions are for reference only!