4. (6 points) Fill in each box with a digit so that the multiplication problem is correct, then the product of this equation is $\qquad$


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【Answer】Solution: First, based on the result number having a tail number of 5, one of the two unit digits of the multipliers is 5 and the other is an odd number,

If the unit digit of the first multiplier is 5, then the next number's tail would be either 0 or 5, which does not meet the condition, so the unit digit of the second multiplier is 5,

Furthermore, based on the first result being a multiple of 5 and the result being in the 200s, the tens digit of the first multiplier is likely 4. Based on the result containing the digits 01, the condition is met by $3 \times 7=21$, so $4 \times 7$ plus the carry-over of 2 fits the condition, i.e., $43 \times 75=3225$
Therefore, the answer is: 3225