Factors worksheet for learning about factors and prime numbers.

Let’s solve this step by step.

We need to find all the factors of each number from 1 to 24.
A factor is a number that divides into another number exactly — no remainder.

Also, we’re told:
> Numbers that have exactly 2 factors (1 and themselves) are called prime numbers.
We’ll highlight those at the end.

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Let’s go one number at a time:

Number 7:
What multiplies to make 7? Only 1 × 7 → Factors: 1, 7

Number 8:
1 × 8 = 8
2 × 4 = 8
→ Factors: 1, 2, 4, 8

Number 9:
1 × 9 = 9
3 × 3 = 9
→ Factors: 1, 3, 9

Number 10:
1 × 10 = 10
2 × 5 = 10
→ Factors: 1, 2, 5, 10

Number 11:
Only 1 × 11 → Factors: 1, 11

Number 12:
1 × 12
2 × 6
3 × 4
→ Factors: 1, 2, 3, 4, 6, 12

Now the right column:

Number 13:
Only 1 × 13 → Factors: 1, 13

Number 14:
1 × 14
2 × 7
→ Factors: 1, 2, 7, 14

Number 15:
1 × 15
3 × 5
→ Factors: 1, 3, 5, 15

Number 16:
1 × 16
2 × 8
4 × 4
→ Factors: 1, 2, 4, 8, 16

Number 17:
Only 1 × 17 → Factors: 1, 17

Number 18:
1 × 18
2 × 9
3 × 6
→ Factors: 1, 2, 3, 6, 9, 18

Number 19:
Only 1 × 19 → Factors: 1, 19

Number 20:
1 × 20
2 × 10
4 × 5
→ Factors: 1, 2, 4, 5, 10, 20

Number 21:
1 × 21
3 × 7
→ Factors: 1, 3, 7, 21

Number 22:
1 × 22
2 × 11
→ Factors: 1, 2, 11, 22

Number 23:
Only 1 × 23 → Factors: 1, 23

Number 24:
1 × 24
2 × 12
3 × 8
4 × 6
→ Factors: 1, 2, 3, 4, 6, 8, 12, 24

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Now, let’s list which numbers have exactly 2 factors — these are the prime numbers:

From 1 to 24:

- 2 → factors: 1,2 → ✔ prime
- 3 → 1,3 → ✔ prime
- 5 → 1,5 → ✔ prime
- 7 → 1,7 → ✔ prime
- 11 → 1,11 → ✔ prime
- 13 → 1,13 → ✔ prime
- 17 → 1,17 → ✔ prime
- 19 → 1,19 → ✔ prime
- 23 → 1,23 → ✔ prime

Note: 1 has only 1 factor → NOT prime.

So primes between 1 and 24:
2, 3, 5, 7, 11, 13, 17, 19, 23

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Final Answer:

Here is the completed table:

| NUMBER | FACTORS | NUMBER | FACTORS |
|--------|-------------------|--------|---------------------|
| 1 | 1 | 13 | 1,13 |
| 2 | 1,2 | 14 | 1,2,7,14 |
| 3 | 1,3 | 15 | 1,3,5,15 |
| 4 | 1,2,4 | 16 | 1,2,4,8,16 |
| 5 | 1,5 | 17 | 1,17 |
| 6 | 1,2,3,6 | 18 | 1,2,3,6,9,18 |
| 7 | 1,7 | 19 | 1,19 |
| 8 | 1,2,4,8 | 20 | 1,2,4,5,10,20 |
| 9 | 1,3,9 | 21 | 1,3,7,21 |
| 10 | 1,2,5,10 | 22 | 1,2,11,22 |
| 11 | 1,11 | 23 | 1,23 |
| 12 | 1,2,3,4,6,12 | 24 | 1,2,3,4,6,8,12,24 |

Prime numbers from 1 to 24 (highlighted):
2, 3, 5, 7, 11, 13, 17, 19, 23