Factors of a number are the numbers that can be multiplied by to get the original number.

To factor a number is to break it into smaller number.

(a) 24

1 × 24 = 24

2 × 12 = 24

3 × 8 = 24

4 × 6 = 24

So,

1, 2, 3, 4, 6, 8, 12 and 24 are the factors of 24.

(b) 15

1 × 15 = 15

3 × 5 = 15

So,

1, 3, 5 and 15 are the factors of 15.

(c) 21

1 × 21 = 21

3 × 7 =21

So,

Factors of 21 are 1, 3, 7 and 21.

(d) 27

1 × 27 =27

3 × 9 = 27

So,

1, 3, 9 and 27 are the factors of 27.

(e) 12

1 × 12 =12

2 × 6 =12

3 × 4 =12

So,

1, 2, 3, 4, 6 and 12 are the factors of 12.

(f) 20

1 × 20 =20

2 × 10 =20

4 × 5 = 20

So,

1, 2, 4, 5, 10 and 20 are the factors of 20.

(g) 18

1 × 18 =18

2 × 9 =18

3 × 6 =18

So,

1, 2, 3, 6, 9, and 18 are the factors of 18.

(h) 23

1 × 23 =23

So,

1 and 23 are the factors of 23.

(i) 36

1 × 36 = 36

2 × 18 = 36

3 × 12 = 36

4 × 9 = 36

6 × 6 = 36

So,

Factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18 and 36.