Thursday, October 25, 2012

Amazing Number: 1089

It's really amazing, try it and have a Math Fun....!!!

Do the following steps for Math fun.....
1) Write down any three-digit number whose digits are decreasing.
2) Reverse the  number.
3) Subtract that reverse number to original number.
4) Add the result and reverse of result number.
5) Then, you will get 1089.

For example.....
942 - 249 = 693
693+396 = 1089.

Reason behind this Amazing number....1089
                     If we let a, b, c denote the three digits of the original number, then the three-digit number is 100a+10b+c. The reverse is 100c+10b+a. Subtract: (100a+10b+c)-(100c+10b+a) to get 99(a-c). Since the digits were decreasing, (a-c) is at least 2 and no greater than 9, so the result must be one of 198, 297, 396, 495, 594, 693, 792, or 891. When you add any one of those numbers to the reverse of itself, you get 1089!

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