31 ( they are : 4,6,9,10,12,14,15, 16,18,20,21,22,24,25,26,27, 28, 30, 32,33,34,35,36,38,40,42,44,45,46,48,49)
There are 15 prime numbers less than 50
positive square numbers less than 50 are 7 these are : 1,4,9,16,25,36,49.These are less than 50.
There are 15 composite numbers greater than 50 but less than 70
There are 15 prime numbers less than 50.
14 of them.
25
100
4
4
There are 18.
There is only one and it is 2
5