(1)
Factors of 45: 1, 3, 5, 9, 15, 45
Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
Common factors of 45 and 30: 1, 3, 5, 15
∴ HCF of 45 and 30 = 15
(2)
Factors of 16: 1, 2, 4, 8, 16
Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
Common factors of 16 and 48: 1, 2, 4, 8, 16
∴ HCF of 16 and 48 = 16
(3)
Factors of 39: 1, 3, 13, 39
Factors of 25: 1, 5, 25
Common factors of 39 and 25: 1
∴ HCF of 39 and 25 = 1
(4)
Factors of 49: 1, 7, 49
Factors of 56: 1, 2, 4, 7, 8, 14, 28, 56
Common factors of 49 and 56: 1, 7
∴ HCF of 49 and 56 = 7
(5)
Factors of 120: 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120
Factors of 144: 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144
Common factors of 120 and 144: 1, 2, 3, 4, 6, 8, 12, 24
∴ HCF of 120 and 144 = 24
(6)
Factors of 81: 1, 3, 9, 27, 81
Factors of 99: 1, 3, 9, 11, 33, 99
Common factors of 81 and 99: 1, 3, 9
∴ HCF of 81 and 99 = 9
(7)
Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24
Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
Common factors of 24 and 36: 1, 2, 3, 4, 6, 12
∴ HCF of 24 and 36 = 12
(8)
Factors of 25: 1, 5, 25
Factors of 75: 1, 3, 5, 15, 25, 75
Common factors of 25 and 75: 1, 5, 25
∴ HCF of 25 and 75 = 25
(9)
Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
Factors of 54: 1, 2, 3, 6, 9, 18, 27, 54
Common factors of 48 and 54: 1, 2, 3, 6
∴ HCF of 48 and 54 = 6
(10)
Factors of 150: 1, 2, 3, 5, 6, 10, 15, 25, 30, 50, 75, 150
Factors of 225: 1, 3, 5, 9, 15, 25, 45, 75, 225
Common factors of 150 and 225: 1, 3, 5, 15, 25, 75
∴ HCF of 150 and 225 = 75