90 palindromes.
From 10 - 99, there are 9 (9 x 1) From 100 - 999, there are 90 (9 x 10) From 1000 - 9999, there are 90 (9 x 10) From 10000 - 99999, there are 900 (9 x 10 x 10) And 100000 itself is not a palindrome. Total: 1089
1, 3, 9, 11, 33, 99, 101, 303, 909, 1111, 3333 and 9999.
The sum of all numbers between 1 and n = n*(n+1)/2 The sum of all numbers between 1 and 999 = 999*1000/2 = 499500 The sum of all numbers between 1 and 9999 = 9999*10000/2 = 49995000 So, the sum of all numbers between 1000 and 9999 = 49495500
9999
There are 10 palindromes divisible by 9 between 1000 and 9999.
90 palindromes.
There are 2828 integers between 1000 and 9999.
5445 is one that I can think of
There are 1,000 positive integers between 1,000 and 9,999, inclusive, that are divisible by nine.
Prime No: between 1000 to 9999= 54_( 42x3)
From 10 - 99, there are 9 (9 x 1) From 100 - 999, there are 90 (9 x 10) From 1000 - 9999, there are 90 (9 x 10) From 10000 - 99999, there are 900 (9 x 10 x 10) And 100000 itself is not a palindrome. Total: 1089
500 of them.
From 1000 to 9999 (inclusive) there are 9999 - 1000 + 1 = 9000 integers. Half of which are even, half of which are odd. So the answer is 9000/2 = 4,500.
1, 3, 9, 11, 33, 99, 101, 303, 909, 1111, 3333 and 9999.
There are 3168 such numbers.
Anything that has 4 digits - any number between 1000 and 9999.