## Dhaka Junior 2011/5

Problem for Junior Group from Divisional Mathematical Olympiad will be solved here.
Forum rules
Please don't post problems (by starting a topic) in the "Junior: Solved" forum. This forum is only for showcasing the problems for the convenience of the users. You can post the problems in the main Divisional Math Olympiad forum. Later we shall move that topic with proper formatting, and post in the resource section.
Moon
Site Admin
Posts: 751
Joined: Tue Nov 02, 2010 7:52 pm
Location: Dhaka, Bangladesh
Contact:

### Dhaka Junior 2011/5

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?
"Inspiration is needed in geometry, just as much as in poetry." -- Aleksandr Pushkin

Please install LaTeX fonts in your PC for better looking equations,
learn how to write equations, and don't forget to read Forum Guide and Rules.

Mehfuj Zahir
Posts: 78
Joined: Thu Jan 20, 2011 10:46 am

### Re: Dhaka Junior 2011/5

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

surjo
Posts: 2
Joined: Fri Oct 05, 2012 2:52 pm

### Re: Dhaka Junior 2011/5

I did not get it. 9*9=81 should be palindromic numbers

Shafin
Posts: 6
Joined: Thu Dec 27, 2012 3:05 pm

### Re: Dhaka Junior 2011/5

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
© Shafin Ahmed

abrarfiaz
Posts: 4
Joined: Mon Mar 20, 2017 4:53 pm

### Re: Dhaka Junior 2011/5

it will be 90

abrarfiaz
Posts: 4
Joined: Mon Mar 20, 2017 4:53 pm

### Re: Dhaka Junior 2011/5

surjo wrote:I did not get it. 9*9=81 should be palindromic numbers

mate it will be 9 * 10