1. Find the HCF of the following numbers :
(a) 18, 48 (b) 30, 42
(c) 18, 60 (d) 27, 63
(e) 36, 84 (f) 34, 102
(g) 70, 105, 175 (h) 91, 112, 49
(i) 18, 54, 81 (j) 12, 45, 75
(a) 18, 48
18 = 2 x 3 x 3
48 = 2 x 2 x 2 x 2 x 3
HCF = 2 x 3 =6
(b) 30, 42
30 = 2 x 3 x 5
42 = 2 x 3 x 7
HCF = 2 x 3 =6
(c) 18, 60
18 = 2 x 3 x 3
60 = 2 x 2 x 3 x 5
HCF = 2 x 3 = 6
(d) 27, 63
27 = 3 x 3 x 3
63 = 3 x 3 x 7
HCF = 3 x 3 = 9
(e) 36, 84
36 = 2 x 3 x 3 x 3
84 = 2 x 2 x 3 x 7
HCF = 2 x 2 x 3 = 12
(f) 34, 102
34 = 2 x 17
102 = 2 x 3 x 17
HCF = 2 x 17 = 34
(g) 70, 105, 175
70 = 2 x 5 x 7
105 = 3 x 5 x 7
175 = 5 x 5 x 7
HCF = 5 x 7 = 35
(h)91, 112, 49
91 = 7 x 13
112 = 2 x 2 x 2 x 2 x 7
49 = 7 x 7
HCF = 7
(i) 18, 54, 81
18 = 2 x 3 x 3
54= 2 x 3 x 3 x 3
81 = 3 x 3 x 3 x 3
HCF = 3 x 3 = 9
(j) 12, 45, 75
12 = 2 x 2 x 3
45 = 3 x 3 x 5
75 = 3 x 5 x 5
HCF = 2