25
Seven of them.
There are 6 odd numbers that are greater than 6 but less than 19. The odd numbers between 6 and 19 are 7, 9, 11, 13, 15, and 17.
Six
No. Odd numbers can be greater than, smaller than, or equal to prime numbers.
There are 30 whole numbers that are odd numbers less than 60 which are also positive. Otherwise, there are infinitely many of them.
17 odd numbers.
25
Seven of them.
There are 6 odd numbers that are greater than 6 but less than 19. The odd numbers between 6 and 19 are 7, 9, 11, 13, 15, and 17.
25
Six
No. Odd numbers can be greater than, smaller than, or equal to prime numbers.
5
5
30
If odd natural numbers are less than 8, then they are prime.