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Dhaka Junior 2011/5

Posted: Wed Feb 02, 2011 8:23 am
by Moon
5. A palindrome, such as $83438$, is a number that remains the same when its digits are reversed. How many four digit numbers are not palindromes?

Re: Dhaka Junior 2011/5

Posted: Wed Feb 02, 2011 3:21 pm
by Mehfuj Zahir
Four digit palindrome number should be like ABBA.If u reverse it u will get also ABBA.At first we will count how many numbers are palindrome.It is enough to count AB.SO we will get the result 9o.Then the ans 10000-90=9910

Re: Dhaka Junior 2011/5

Posted: Mon Dec 31, 2012 8:41 pm
by surjo
I did not get it. 9*9=81 should be palindromic numbers

Re: Dhaka Junior 2011/5

Posted: Mon Jan 14, 2013 8:02 pm
by Shafin
Mehfuj Zahir wrote:Four digit palindrome number should be like ABBA.If u reverse it u will get also ABBA.At first we will count how many numbers are palindrome.It is enough to count AB.SO we will get the result 9o.Then the ans 10000-90=9910
4 digit number starts from 1000 so
there are 9000 4 digit numbers therefore the answer should be 8910

Re: Dhaka Junior 2011/5

Posted: Sat Nov 18, 2017 7:50 pm
by abrarfiaz
it will be 90

Re: Dhaka Junior 2011/5

Posted: Sat Nov 18, 2017 7:52 pm
by abrarfiaz
surjo wrote:I did not get it. 9*9=81 should be palindromic numbers


mate it will be 9 * 10