9999
5335
9,999,876 is the greatest seven-digit number using four different digits.
The first digit can be any one of nine (all except zero). For each of those . . .The second digit can be any one of ten.Total possibilities for the first two digits = 9 x 10 = 90.Since the 4-digit number is a palindrome, the 3rd and 4th digits are determinedby the 1st and 2nd ones.So the total number of 4-digit palindromes is the same as the number of possibilitiesfor the first 2 digits = 90 .
9876 is the largest four digit number you can make if all the digits must be different.
9999
5335
9347 is not a digit but four digits.
If you realize that a 4 digit palindrome is basically a two digit number followed by it's own reverse, you can re-phrase this question as 'how many two digit numbers are there?' Which would then mean that (if you're considering zeros as digits without a non-zero leading term) there would be a 4 digit palindrome 0000 for the two digit 00; a four digit 0110 for the two digit 01; 0220, 02; etc etc. So the number of four digit palindromes would be the same as the quantity of whole numbers from 00 to 99. So I believe the total answer to your question would be 100.
9,999,876 is the greatest seven-digit number using four different digits.
1221
The first digit can be any one of nine (all except zero). For each of those . . .The second digit can be any one of ten.Total possibilities for the first two digits = 9 x 10 = 90.Since the 4-digit number is a palindrome, the 3rd and 4th digits are determinedby the 1st and 2nd ones.So the total number of 4-digit palindromes is the same as the number of possibilitiesfor the first 2 digits = 90 .
the answer is ofcourse 9999. If you insist that the first and second digit be different then it would be 9889.
9876 is the largest four digit number you can make if all the digits must be different.
The greatest 4-digit number with no repeated digits is... 9876
Find a four digit number whose digits will be reversed when multiplied by nine?
Any pair of digits (not including 0), can be used to generate 14 four-digit numbers. If one of the digits is 0, only seven will start with a non-zero digit.