14
221
11 and 18
11 and 16.
11 is a tricky one, but this is how:if the sum of every other digit minus the sum of all the other digits equals a multiple of 11example:Q: Is 164725 divisible by 11?A: Yes. and this is why... first you take every other digit 164725, then add them 6+7+5=18. Now take the rest of the numbers 164725 and add them, 1+4+2=7. After that subtract them, 18-7=11, and 11 is a multiple of 11 (11x1=11).
All two digit numbers which the digits add up to 11 are :- 29, 38, 47, 56, 65, 74, 83 & 92.
There are 199 palindromic numbers between 0 and 1000. These include single-digit numbers (0-9), which total 10, and two-digit numbers (11, 22, ..., 99), which add up to 9. Additionally, there are 90 three-digit palindromic numbers, ranging from 101 to 999, that follow the format aba (where a and b are digits). Thus, the total is 10 (single-digit) + 9 (two-digit) + 90 (three-digit) = 109 palindromic numbers.
The digital root of a number is found by repeatedly summing its digits until a single digit is obtained. For the number 11, you add the digits: 1 + 1 = 2. Since 2 is a single digit, the digital root of 11 is 2.
There are 199 palindromic numbers between 0 and 1000. These include single-digit numbers (0 to 9), two-digit numbers (e.g., 11, 22, ... 99), and three-digit numbers (e.g., 101, 111, ... 999). Each of these categories contributes to the total, with the three-digit palindromes being in the form of ABA, where A and B are digits.
You can select 12 numbers for the first digit, 11 numbers for the second digit, and 10 numbers for the third digit; so 12*11*10 = 1320 sets of 3 numbers can be made out of 12 different numbers.
14
99990 Note that if you add 11 to my answer you get a 6-digit number therefore it must be the largest 5-digit whole multiple of 11.
221
Eleven digit numbers are those in the range between 9,999,999,999 and 100,000,000,000 exclusive. There are 90,000,000,000 of these.
11
11
Palindromic numbers between 1 and 1000 are numbers that read the same forward and backward. The palindromic numbers in this range include single-digit numbers (1 to 9), two-digit numbers like 11, 22, 33, up to 99, and three-digit numbers such as 101, 111, 121, up to 999. Specifically, the three-digit palindromes follow the pattern ABA, where A and B are digits. In total, there are 199 palindromic numbers between 1 and 1000.
There are more 12-digit palindromic numbers than 11-digit palindromic numbers. This is because the number of possible 12-digit palindromic numbers is greater than the number of possible 11-digit palindromic numbers. In general, the number of palindromic numbers of length n is 9 * 10^((n-1)/2), so for 11-digit palindromic numbers, there are 9 * 10^5 = 900,000 possibilities, while for 12-digit palindromic numbers, there are 9 * 10^6 = 9,000,000 possibilities.