Prime numbers worksheet | Worsheets library - Free Printable

Let's solve the problem step by step.

Task:

Circle the prime numbers from the list of numbers given in the worksheet.

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What is a Prime Number?

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
For example:
- 2 is prime (divisible only by 1 and 2)
- 3 is prime
- 4 is not prime (divisible by 1, 2, 4)

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Given Numbers:

We are to identify which numbers in this grid are prime:

```
18 27 23 8 7
33 39 37 22 16
3 6 9 5 11
30 41 36 25 29
17 32 38 13 47
30 38 28 16 40
5 25 35 45 15
16 4 2 12 18
```

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Step-by-step Check for Each Number:

We will go through each number and determine if it’s prime.

#### Row 1:
- 18: divisible by 2, 3, 6, 9 → Not prime
- 27: divisible by 3, 9 → Not prime
- 23: only divisible by 1 and 23 → ✔ Prime
- 8: divisible by 2, 4 → Not prime
- 7: only divisible by 1 and 7 → ✔ Prime

#### Row 2:
- 33: divisible by 3, 11 → Not prime
- 39: divisible by 3, 13 → Not prime
- 37: only divisible by 1 and 37 → ✔ Prime
- 22: divisible by 2, 11 → Not prime
- 16: divisible by 2, 4, 8 → Not prime

#### Row 3:
- 3: only divisible by 1 and 3 → ✔ Prime
- 6: divisible by 2, 3 → Not prime
- 9: divisible by 3 → Not prime
- 5: only divisible by 1 and 5 → ✔ Prime
- 11: only divisible by 1 and 11 → ✔ Prime

#### Row 4:
- 30: divisible by 2, 3, 5, 6, 10, 15 → Not prime
- 41: only divisible by 1 and 41 → ✔ Prime
- 36: divisible by 2, 3, 4, 6, 9, 12, 18 → Not prime
- 25: divisible by 5 → Not prime
- 29: only divisible by 1 and 29 → ✔ Prime

#### Row 5:
- 17: only divisible by 1 and 17 → ✔ Prime
- 32: divisible by 2, 4, 8, 16 → Not prime
- 38: divisible by 2, 19 → Not prime
- 13: only divisible by 1 and 13 → ✔ Prime
- 47: only divisible by 1 and 47 → ✔ Prime

#### Row 6:
- 30: already checked → Not prime
- 38: already checked → Not prime
- 28: divisible by 2, 4, 7, 14 → Not prime
- 16: already checked → Not prime
- 40: divisible by 2, 4, 5, 8, 10, 20 → Not prime

#### Row 7:
- 5: already checked → ✔ Prime
- 25: already checked → Not prime
- 35: divisible by 5, 7 → Not prime
- 45: divisible by 3, 5, 9, 15 → Not prime
- 15: divisible by 3, 5 → Not prime

#### Row 8:
- 16: already checked → Not prime
- 4: divisible by 2 → Not prime
- 2: only divisible by 1 and 2 → ✔ Prime
- 12: divisible by 2, 3, 4, 6 → Not prime
- 18: already checked → Not prime

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✔ Final List of Prime Numbers:

From the above analysis, the prime numbers are:

23, 7, 37, 3, 5, 11, 41, 29, 17, 13, 47, 5, 2

Wait — 5 appears twice, and 2 appears once. But we should list each unique prime only once, or circle all occurrences.

But since the task is to circle the prime numbers, we must identify all instances in the grid.

So let's list all prime numbers in the grid:

- 23 → one occurrence
- 7 → one
- 37 → one
- 3 → one
- 5 → two times (one in row 3, one in row 7)
- 11 → one
- 41 → one
- 29 → one
- 17 → one
- 13 → one
- 47 → one
- 2 → one

So total 13 prime numbers in the grid.

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✔ Answer: Circle these numbers:

> 23, 7, 37, 3, 5, 11, 41, 29, 17, 13, 47, 5, 2

Note: The number 5 appears twice — both should be circled.

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🟩 Summary:

The prime numbers between 2–50 in this grid are:

> 2, 3, 5, 7, 11, 13, 17, 23, 29, 37, 41, 47

And in the grid, they appear as:
- 23 ✔
- 7 ✔
- 37 ✔
- 3 ✔
- 5 ✔ (twice)
- 11 ✔
- 41 ✔
- 29 ✔
- 17 ✔
- 13 ✔
- 47 ✔
- 2 ✔

All others are composite or not prime.

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✔ Final Answer: Circle the following numbers in the grid:
> 2, 3, 5, 5, 7, 11, 13, 17, 23, 29, 37, 41, 47

(That’s 13 numbers to circle — including the duplicate 5.)