Prime and composite numbers worksheet for identifying and circling numbers from 1 to 50.

Let’s solve this step by step.

We are asked to:
1. Circle all the prime numbers from 1 to 50.
2. Circle all the composite numbers from 1 to 50.
3. Remember: 1 is neither prime nor composite.

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Step 1: What is a prime number?

A prime number is a whole number greater than 1 that has exactly two factors: 1 and itself.
Examples: 2, 3, 5, 7 — because you can’t divide them evenly by any other number except 1 and themselves.

Step 2: What is a composite number?

A composite number is a whole number greater than 1 that has more than two factors.
Examples: 4 (factors: 1, 2, 4), 6 (factors: 1, 2, 3, 6)

Step 3: List numbers from 1 to 50 and classify them

We’ll go one by one:

- 1 → Not prime, not composite → skip both lists
- 2 → Prime (only divisible by 1 and 2)
- 3 → Prime
- 4 → Composite (divisible by 1, 2, 4)
- 5 → Prime
- 6 → Composite
- 7 → Prime
- 8 → Composite
- 9 → Composite (3×3)
- 10 → Composite
- 11 → Prime
- 12 → Composite
- 13 → Prime
- 14 → Composite
- 15 → Composite
- 16 → Composite
- 17 → Prime
- 18 → Composite
- 19 → Prime
- 20 → Composite
- 21 → Composite (3×7)
- 22 → Composite
- 23 → Prime
- 24 → Composite
- 25 → Composite (5×5)
- 26 → Composite
- 27 → Composite (3×9)
- 28 → Composite
- 29 → Prime
- 30 → Composite
- 31 → Prime
- 32 → Composite
- 33 → Composite (3×11)
- 34 → Composite
- 35 → Composite (5×7)
- 36 → Composite
- 37 → Prime
- 38 → Composite
- 39 → Composite (3×13)
- 40 → Composite
- 41 → Prime
- 42 → Composite
- 43 → Prime
- 44 → Composite
- 45 → Composite
- 46 → Composite
- 47 → Prime
- 48 → Composite
- 49 → Composite (7×7)
- 50 → Composite

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Now let’s list them clearly:

#### Prime Numbers (circle these in first box):
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47

→ That’s 15 prime numbers between 1 and 50.

#### Composite Numbers (circle these in second box):
All numbers from 2 to 50 EXCEPT the primes above, and excluding 1.

So composites are:
4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50

→ That’s 34 composite numbers.

(Check: Total numbers 1–50 = 50
Minus 1 (neither) = 49
Primes = 15 → Composites should be 49 - 15 = 34 ✔)

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Final Answer:

Prime numbers to circle (first box):
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47

Composite numbers to circle (second box):
4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50