To understand the difference between prime and composite numbers, let’s first define each:
- Prime Numbers: These are natural numbers greater than 1 that have no positive divisors other than 1 and themselves. In simpler terms, a prime number can only be divided evenly (without leaving a remainder) by 1 and the number itself.
- Composite Numbers: These are natural numbers greater than 1 that are not prime. This means they have more than two positive divisors. In other words, a composite number can be divided evenly by numbers other than 1 and itself.
Now, let’s list the prime and composite numbers less than 20:
Prime Numbers less than 20:
- 2
- 3
- 5
- 7
- 11
- 13
- 17
- 19
Composite Numbers less than 20:
- 4
- 6
- 8
- 9
- 10
- 12
- 14
- 15
- 16
- 18
In summary, the prime numbers less than 20 are 2, 3, 5, 7, 11, 13, 17, and 19, while the composite numbers are 4, 6, 8, 9, 10, 12, 14, 15, 16, and 18. Understanding these classifications helps in many areas of mathematics, especially in number theory.