Write down separately the prime and composite numbers less than 20.

Explanation

To solve the question of identifying prime and composite numbers less than 20, we will follow these steps:

### Step 1: Understand the definitions
- **Prime Number**: A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. This means it can only be divided evenly by 1 and the number itself.
- **Composite Number**: A composite number is a natural number greater than 1 that has more than two positive divisors. This means it can be divided evenly by numbers other than 1 and itself.

### Step 2: List the numbers less than 20
The numbers less than 20 are:
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