One of them.
Set of even numbers less than 50 and more than 40 = {42,44,46,48}
is a set of even numbers less than 8
The even whole numbers greater than 21 and less than 28 are: 22, 24 and 26
There are 899 numbers that are less than 900
One of them.
There is only one and it is 2
49 of them.
If you include negative numbers, that's an infinite list.
100
Only one number can be both even and prime, and that is the number 2.
Set of even numbers less than 50 and more than 40 = {42,44,46,48}
is a set of even numbers less than 8
None. All counting numbers are even or odd.
The even whole numbers greater than 21 and less than 28 are: 22, 24 and 26
There are 899 numbers that are less than 900
All numbers are either odd or even, none are both, so less than 30 there are 29 counting numbers that are either odd or even but not both. (Assuming you mean starting to count with 1.)