Let the original number be x 1x2x3x4x5x6, and the new number be 2x18x x 3x4x5x6.

Because it is 8 1 times the original number, let the new number subtract the original number first.

=2x 1(8-x 1)00000, which is 80 times the original number.

Then 2x 1(8-x 1)0000 is eight times the original number,

Then the divisor is 8, the dividend is 2x 1(8-x 1)0000, and the quotient is x 1x2x3x4x5x6, so we know that the rough judgment of x 1 is 2 and 3, and we know that it can only be 2-3 after careful judgment, which will lead to insufficient divisor. 0 is wrong-so just keep inferring.

x2=8

x3=2

x4=5

x5=0

x6=0

So we know that the original telephone number is 282500.

You can go back to the original calculation and know that the answer is correct.