The answer is 325* 147=47775. I did it by trial calculation. First look at the result of number multiplication. If the unit is equal to 5 and the multiplier is 5, then the multiplicand should be 1, 3,5,7,9. But comprehensively, when the unit is 1, 3, 5. When I choose a number 7, I choose a multiplier of 100 digits in the second step. Because the product is four digits, and the unit number is 7, and the product is more than 2000, you can't choose too large a hundred digits. If I choose 4, it may be greater than the result, so I choose 3. I guess the other two numbers are the same. I wonder if you will adopt this stupid method? That's what I do when I do this kind of topic.