October 3, 2019

To find all the natural numbers which gets reverse when multiplied by 9


To find all the natural numbers which gets reverse when multiplied by 9
1089 = 33×33
1089 ×9 = 9801 = 99×99
1089 is the smallest natural number which gets reverse when multiplied by 9.
There is interesting pattern for all the numbers.
 



1089 × 9 = 9801
10989 ×9 = 98901
109989 × 9 = 989901
1099989×9 = 9899901
10999989×9 = 98999901 
10891089×9 = 98019801
 ..............  
If number of digits in number is not  multiple of 4 then only one number is possible.
10999…(n-4) times 89 ×9 =98999…..(n-4) times 01
 Where n is number of digits.

If number of digits in the number  is multiple of 4 then 1 more number is possible.
10891089 × 9 = 98019801
10891089…….1089 × 9 = 98019801……….9801

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