Ks1859 wrote:
A positive integer is a palindrome if it reads exactly the same from right to left as it does from left to right. For example, 5 and 66 and 373 are all palindromes. How many palindromes are there between 1 and 1,000, inclusive?
Single digit numbers (_), we can pick from 9 numbers
2-digit numbers (_)(_), we can pick 9 numbers for the first blank and those 9 again for the second blank
So, (9)(1) = 9 numbers
3-digit numbers (_)(_)(_), we can pick 9 numbers for the first blank, 10 for the second blank and those 9 again for the third blank
So, (9)(10)(1) = 90 numbers
Total = 9 + 9 + 90 = 108