Write all the factors of the following numbers:
(a) 24
(b) 15
(c) 21
(d) 27
(e) 12
(f) 20
(g) 18
(h) 23
(i) 36
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(a) 24
24 = 1 × 24
24 = 2 × 12
24 = 3 × 8
24 = 4 × 6
24 = 6 × 4
Stop here since 4 and 6 have occurred earlier
Hence, the factors of 24 are 1, 2, 3, 4, 6, 8, 12 and 24
(b) 15
15 = 1 × 15
15 = 3 × 5
15 = 5 × 3
Stop here since 3 and 5 have occurred earlier
Hence, the factors of 15 are 1, 3, 5 and 15
(c) 21
21 = 1 × 21
21 = 3 × 7
21 = 7 × 3
Stop here since 3 and 7 have occurred earlier
Hence, the factors of 21 are 1, 3, 7 and 21
(d) 27
27 = 1 × 27
27 = 3 × 9
27 = 9 × 3
Stop here since 3 and 9 have occurred earlier
Hence, the factors of 27 are 1, 3, 9 and 27
(e) 12
12 = 1 × 12
12 = 2 × 6
12 = 3 × 4
12 = 4 × 3
Stop here since 3 and 4 have occurred earlier
Hence, the factors of 12 are 1, 2, 3, 4, 6 and 12
(f) 20
20 = 1 × 20
20 = 2 × 10
20 = 4 × 5
20 = 5 × 4
Stop here since 4 and 5 have occurred earlier
Hence, the factors of 20 are 1, 2, 4, 5, 10 and 20
(g) 18
18 = 1 × 18
18 = 2 × 9
18 = 3 × 6
18 = 6 × 3
Stop here since 3 and 6 have occurred earlier
Hence, the factors of 18 are 1, 2, 3, 6, 9 and 18
(h) 23
23 = 1 × 23
23 = 23 × 1
Since 1 and 23 have occurred earlier
Hence, the factors of 23 are 1 and 23
(i) 36
36 = 1 × 36
36 = 2 × 18
36 = 3 × 12
36 = 4 × 9
36 = 6 × 6
Stop here since both the factors (6) are the same. Thus the factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18 and 36