# What word is the same backwards and upside down riddle?

Palindrome

## What is the next year that will be a palindrome?

The next full palindrome date will occur on Dec. 12, 2121, ( or 101 years from now. Inan has also compiled a list of seven- and eight-digit palindrome dates in the 21st century.

How many palindromes are there?

Of the 900 five-digit palindromes, 93 are prime. There are 668 prime palindromes with seven digits. Among palindromes with an odd number of digits, the ratio of primes to composites becomes smaller and smaller as the number of digits increases.

What are the numbers divisible by 11?

If that is divisible by 11, so is the original number. So, for instance, 2728 has alternating sum of digits 2 – 7 + 2 – 8 = -11. Since -11 is divisible by 11, so is 2728. Similarly, for 31415, the alternating sum of digits is 3 – 1 + 4 – 1 + 5 = 10.

### Which number is not divisible by 11?

Now, we can clearly see only the number 888888 gives the number as 0 which is divisible by 11 and all other numbers are not divisible by 11. Therefore the total number of numbers which are not divisible by 11 are 6.

### What is the rule for dividing by 11?

Divisibility rules for numbers 1–30DivisorDivisibility condition11Form the alternating sum of the digits. The result must be divisible by 11.Add the digits in blocks of two from right to left. The result must be divisible by 11.Subtract the last digit from the rest. The result must be divisible by 11.64

Why does the divisibility rule for 11 work?

Divisibility by 11 Any number whose absolute difference between the sum of digits in the even positions and the sum of digits in the odd positions is 0 0 0 or divisible by is itself also divisible by

How do you find if a number is a multiple of 11?

Starting from the right hand end of the number and moving to the left, take the first digit, subtract the next digit, add the one after that, subtract the next and so on, alternately subtracting and adding the digits. If the resulting number is a multiple of 11, so is the original number.