9 and 15 are the only two odd composite numbers less than twenty.
15 and 9 are both odd, composite numbers less than 20.
15
9 and 15 only.
9 and 15
9 and 15 only
The composite numbers up to 20 are 4,6,8,9,12,14,15,16,18 and 20.
The odd prime numbers less than 20 are 3, 5, 7, 11, 13, 17, and 19.
The first 20 odd numbers are: 13579111315171921232527293133353739.
15 is a composite number - it can be divided by 3 and 5. 11, 13, 17 and 19 are all prime numbers, not composite.
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Not all numbers between 20 and 28 are composite numbers. 23 is a prime number.