1. The numbers 1 through 99 are 99 different numbers; each one occurs once.
99 of them.
There are 90 two-digit numbers... starting with 10 and ending with 99.
88
From 10 to 99 (inclusive) there are 90 numbers.18 are evenly divisible by 5.Therefore 72 are not.
109
There are 180. 10 through 99 and -10 to -99.
90. all the numbers from 10 through 99
1. The numbers 1 through 99 are 99 different numbers; each one occurs once.
99 of them.
There are 90 two-digit numbers... starting with 10 and ending with 99.
88
25
From 10 to 99 (inclusive) there are 90 numbers.18 are evenly divisible by 5.Therefore 72 are not.
From 1 to 99, there are 99 numbers.The first nine of them ... 1 through 9 ... have only one digit, so discard them.So there are (99 - 9) = 90 positive whole numbers with 2 digits.And another 90 negative whole numbers with 2 digits.
109
99 palindromes.