15 has more than exactly two factors (1, 3, 5, and 15), therefore it is composite. 17, 19, and 23 each have exactly 2 factors (1 and the number itself), so they are primes.
The prime factors of 34 are 2 and 17, and 2 + 17 = 19.
2, 3, 5, and 9 includes one composite number - 9. 3, 11, 23, and 31 are all prime numbers. 2, 5, 15, and 19 includes one composite number - 19. 7, 17, 29, and 49 includes one composite number - 49.
18 (All even numbers except 2 are composite.)
21 is composite.
15 has more than exactly two factors (1, 3, 5, and 15), therefore it is composite. 17, 19, and 23 each have exactly 2 factors (1 and the number itself), so they are primes.
15 is a composite number - it can be divided by 3 and 5. 11, 13, 17 and 19 are all prime numbers, not composite.
It is 15
17, 19, 23, 29 and 31 are prime. 15, 21, 25 and 27 are composite..
15 is. In addition to ' 1 ' and itself, it has the additional factors 3 and 5 .
The prime factors of 34 are 2 and 17, and 2 + 17 = 19.
2, 3, 5, and 9 includes one composite number - 9. 3, 11, 23, and 31 are all prime numbers. 2, 5, 15, and 19 includes one composite number - 19. 7, 17, 29, and 49 includes one composite number - 49.
18 (All even numbers except 2 are composite.)
231517 is composite number. 19 is a prime number.
The composite numbers between 11 and 19 are: 12 14 15 16 18 The other numbers, 11, 13, 17, and 19, are all prime.
All of them except for 11, 13, 17 and 19 which are prime numbers
12, 14, 15, 16, and 18 are composite numbers 11, 13, 17, and 19 are prime numbers