7
Seven of them.
All the prime numbers less than 20 are 2,3,5,7,11,13,17,19
23 and 29 are the two prime numbers greater than 20 but less than 30.
The numbers 23 and 29 are prime.
The set of prime numbers less than 20 = {2, 3, 5, 7, 11, 13, 17,19}
2,3,5,7,11,13,17,19
2,3,5,7,11,13,17,19
Two: 23 29
Two: 23 29
Two. 23 and 29.
There are actually 8 prime numbers less than 20: 2, 3, 5, 7, 11, 13, 17, and 19
There are two prime numbers between 20 and 30 which are 23 and 29