Put simply, composite numbers are numbers that have more than two factors.
Understanding Composite Numbers
Based on the definition, a number that is divisible by a number other than 1 and the number itself, is called a composite number. This means that composite numbers have more than 2 factors. In contrast, a number that is divisible only by 1 and itself is called a prime number.
Think of factors as the numbers you can multiply together to get another number. For example, the factors of 6 are 1, 2, 3, and 6 because:
- 1 x 6 = 6
- 2 x 3 = 6
Since 6 is divisible by 2 and 3 (numbers other than 1 and itself), and it has more than two factors (1, 2, 3, 6), it is a composite number.
Composite vs. Prime Numbers
The key difference between composite and prime numbers lies in their factors:
- Composite Numbers: Have more than two factors. They can be divided evenly by numbers other than 1 and themselves.
- Prime Numbers: Have exactly two factors: 1 and the number itself. They can only be divided evenly by 1 and themselves.
Here are some examples based on the provided definition:
- Composite Numbers: 4, 6
- Prime Numbers: 2, 3, 5
Let's look at the factors:
| Number | Factors | Type | Reason |
|---|---|---|---|
| 2 | 1, 2 | Prime | Only divisible by 1 and itself (2 factors) |
| 3 | 1, 3 | Prime | Only divisible by 1 and itself (2 factors) |
| 4 | 1, 2, 4 | Composite | Divisible by 2 (more than 2 factors) |
| 5 | 1, 5 | Prime | Only divisible by 1 and itself (2 factors) |
| 6 | 1, 2, 3, 6 | Composite | Divisible by 2 and 3 (more than 2 factors) |
Key Takeaways
- Composite numbers are built up from smaller factors other than just 1 and themselves.
- All whole numbers greater than 1 are either prime or composite.
- The number 1 is neither prime nor composite.
In simple terms, if you can divide a number (greater than 1) by any number other than 1 and itself and get a whole number result, it's a composite number.
