Not all of them, just these: 90, 91, 92, 93, 94, 95, 96, 98, 99. (97 is the only prime in that range).
The numbers 90, 91, 92, 93, 94, 95, 96, 98, 99 and 100 are composite (including the boundaries).
There are 10 composite numbers from 90 to 100 (including the boundaries):90, 91, 92, 93, 94, 95, 96, 98, 99 and 100
90
There are 8 composite numbers between 90 and 100. They are 91, 92, 93, 94, 95, 96, 98, and 99.
There are 180. 10 through 99 and -10 to -99.
Add them up. 90, 91, 92, 93, 94, 95, 96, 98, 99, 100
90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 102, 104, 105, 106, 108, 110
90. all the numbers from 10 through 99
The numbers 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99 and 100 are composite (including the boundaries).
They are: 99 and 90
composite numbers are numbers that can be divided by something other than one. in other words, non-prime numbers. thus, these numbers are composite numbers: 86, 96, 85, 87, 99, 100, 82, 84 and these are not composite numbers: 67, 73
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.