Math Drills - Worksheet Digital - Free Printable

To solve this problem, we need to identify which numbers in the grid are prime.

A prime number is a whole number greater than 1 that has exactly two factors: 1 and itself. This means it can only be divided evenly by 1 and the number itself.

Let’s go through each number in the grid and check if it is prime:

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Row 1:
- 6 → divisible by 2 and 3 → not prime
- 5 → only divisible by 1 and 5 → prime
- 32 → even number → divisible by 2 → not prime
- 11 → only divisible by 1 and 11 → prime
- 7 → only divisible by 1 and 7 → prime

Row 2:
- 23 → only divisible by 1 and 23 → prime
- 17 → only divisible by 1 and 17 → prime
- 4 → divisible by 2 → not prime
- 2 → only divisible by 1 and 2 → prime (smallest prime!)
- 51 → 5+1=6 → divisible by 3 → 51 ÷ 3 = 17 → not prime

Row 3:
- 40 → even → not prime
- 25 → 5×5 → not prime
- 41 → only divisible by 1 and 41 → prime
- 19 → only divisible by 1 and 19 → prime
- 9 → 3×3 → not prime

Row 4:
- 3 → only divisible by 1 and 3 → prime
- 31 → only divisible by 1 and 31 → prime
- 60 → even → not prime
- 27 → 3×9 → not prime
- 14 → even → not prime

Row 5:
- 22 → even → not prime
- 13 → only divisible by 1 and 13 → prime
- 57 → 5+7=12 → divisible by 3 → 57 ÷ 3 = 19 → not prime
- 16 → even → not prime
- 7 → already known → prime

Row 6:
- 51 → again, divisible by 3 → not prime
- 9 → not prime
- 29 → only divisible by 1 and 29 → prime
- 42 → even → not prime
- 3 → already known → prime

Row 7:
- 13 → already known → prime
- 50 → even → not prime
- 71 → let’s check: not divisible by 2, 3, 5, 7, or 11 → 71 ÷ 7 ≈ 10.1, 71 ÷ 11 ≈ 6.45 → no whole number divisors → prime
- 30 → even → not prime
- 4 → not prime

Row 8:
- 90 → even → not prime
- 77 → 7×11 → not prime
- 5 → already known → prime
- 25 → 5×5 → not prime
- 8 → even → not prime

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Now, let’s list all the prime numbers found:

From Row 1: 5, 11, 7
From Row 2: 23, 17, 2
From Row 3: 41, 19
From Row 4: 3, 31
From Row 5: 13, 7
From Row 6: 29, 3
From Row 7: 13, 71
From Row 8: 5

Note: Some numbers appear more than once (like 3, 5, 7, 13), but since the task says “circle the prime numbers,” we circle every instance that is prime — even if repeated.

Final list of primes to circle (in order as they appear in the grid):

5, 11, 7,
23, 17, 2,
41, 19,
3, 31,
13, 7,
29, 3,
13, 71,
5

That’s 18 numbers total to circle.

Final Answer:
Circle these numbers: 5, 11, 7, 23, 17, 2, 41, 19, 3, 31, 13, 7, 29, 3, 13, 71, 5