Thursday, 28 January 2016

Weekly Maths (13) :9 Flips 28/03/2015


       abcdefghijkl

X                        9

       lkjihgfedcba


What is the 12 digit number abcdefghijkl ?



Suppose that N is a positive number written base 10, and that 9xN has the same digits as N but in a reversed order. Then we shall say for short that N is a 9-Flip





Find all 9-flips with 12 digits


Is it possible to say exactly how many 9-flips there are with precisely n digits?



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