Factors online exercise for 4 - Free Printable

Let’s solve this step by step.

We are finding factors of numbers.
Factors are pairs of numbers that multiply together to make the product (the number we’re looking at).

For example:
2 × 5 = 10 → so 2 and 5 are factors of 10.

We need to find all factor pairs for each number given, then list them in order from smallest to largest.

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For 20:

Find pairs that multiply to 20:
- 1 × 20 = 20
- 2 × 10 = 20
- 4 × 5 = 20

So the factors are: 1, 2, 4, 5, 10, 20

There are 6 circles — perfect!

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For 27:

Pairs that multiply to 27:
- 1 × 27 = 27
- 3 × 9 = 27

(No other whole numbers work — 2 doesn’t divide 27 evenly, 4 doesn’t, etc.)

So the factors are: 1, 3, 9, 27

There are 4 circles — matches!

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For 12:

Pairs that multiply to 12:
- 1 × 12 = 12
- 2 × 6 = 12
- 3 × 4 = 12

So the factors are: 1, 2, 3, 4, 6, 12

6 circles — good!

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For 15:

Pairs that multiply to 15:
- 1 × 15 = 15
- 3 × 5 = 15

So the factors are: 1, 3, 5, 15

4 circles — correct!

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For 11:

Pairs that multiply to 11:
- 1 × 11 = 11

11 is a prime number — only has two factors.

So the factors are: 1, 11

2 circles — perfect!

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Now, the last part: “List the factors of these numbers”

#### 1. 16
Pairs:
- 1 × 16
- 2 × 8
- 4 × 4 → but we don’t repeat 4 twice

So factors: 1, 2, 4, 8, 16

#### 2. 21
Pairs:
- 1 × 21
- 3 × 7

So factors: 1, 3, 7, 21

#### 3. 23
23 is a prime number — only divisible by 1 and itself.

So factors: 1, 23

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Final Answer:

Fill in the missing factors:

- 20 → 1, 2, 4, 5, 10, 20
- 27 → 1, 3, 9, 27
- 12 → 1, 2, 3, 4, 6, 12
- 15 → 1, 3, 5, 15
- 11 → 1, 11

List the factors:

1. 16 → 1, 2, 4, 8, 16
2. 21 → 1, 3, 7, 21
3. 23 → 1, 23