Pick a four digit number, all digits different, such that when you add its reverse and divide it by 10, you get the number you started with.

For example: 1749+9471=11220, 11220/10 = 1122. Since 1749 is not equal to 1122, this is not the right number.

To divide the number by 10 and get the starting number, the number and its reverse needs to end with a 0. This means that the first and last numbers could be 1 & 9, 2 & 8, 3 & 7 and 4 & 6, but not 5 and 5 because the digits need to be different.

One solution (i dont know if there's more or not) is 1089 because 1089 + 9801 equals 10890, which is ten times 1089, the original number.

Posted by Lewis on 2003-07-06 04:45:24