Choose 6 cards from 123456789 and subtract two three digits. The final equivalent number is 45 1. If you know, please tell me.

It's impossible. This formula consisting of nine numbers is impossible. XXX-XXX=45 1

Now 45 1 has been used up, which means you can still use 236789.

Assuming that the first three digits start with 9, the other three digits start with 4 or 5, because 9-5=4 (no borrowing operation),

9- 1-4=4 (borrowing operation), because 4\5 all appear in 45 1, so the hundred digits can't be 9.

Suppose the hundredth digit is 8, then the hundredth digit of another number is 3 or 4, and 4 appears in 45 1, so it can only be 3 (note that the ten digits of the three digits starting with 8 are smaller than those of the other three digits). Then the beginning of 8 and 3 is settled, and the remaining digits are 2679, of which only 67 is equal to 1, so 100.

Suppose it is 7, then another three-digit number may start with 2 or 3.

Suppose it is 3, (then the ten digits of three digits starting with 7 are greater than the ten digits starting with 3), the remaining digits are 2689, and the subtraction is equal to 1 to 9 and 8, so the three digits are 769 and 328 respectively, and the number is 44 1.

Suppose 2, the numbers 739 and 268 are 47 1.

Suppose it is 6, then the hundred digits of another number can only be 2, because 1 is in 45 1, and the remaining digits are 3789. Suppose the numbers are 7 and 8 respectively, then these three digits are 698 and 237, and the number is 46 1. If the numbers are 9 and 8, then these three numbers are 679 and 238.

That's all. It is impossible to get 45 1.