3. (8 points) As shown in the figure, in a multiplication vertical calculation, $2, 0, 1, 6$ have already been filled in. What is the product? 

Translate the above text into English, please retain the original text's line breaks and format, and output the translation result directly.
【Solution】Solution: First, judge according to the number 0, the tens place of the first number is 5, only $2 \times 5=10$ meets the condition. So the digit before 0 is 1.

Then, judge according to the number 6, which is $1+5=6$, the digit above 6 is 5. The first two-digit number 51 appears.
So in the multiplication, only the digit 1 before 2 meets the condition, and the digit after 0 is 2.
That is, $51 \times 12=612$.
Therefore, the answer is: 612