Answer:
(a) 3, (b) 3
Step-by-step explanation:
HCF is highest common factor. Each number is split into multiples while the common factors are then multiplied together.
(a) HCF of 15, 63, 99
15 = 3 X 5 ----------------------------- (i)
63 = 3 X 3 X 7 ---------------------------(ii)
99 = 3 X 3 X 11 ---------------------------(iii)
From the three equations, 3 is the only common factor; 3 appears in equations (i), (ii) and (iii)
hence the HCF of 15, 63 and 99 is 3
(b) HCF of 66, 33, 78
66 = 2 X 3 X 11 ----------------------------- (iv)
33 = 3 X 11 ---------------------------(v)
78 = 2 X 3 X 13 ---------------------------(vi)
From the three equations, 3 is still the only common factor; 3 appears in equations (iv), (v) and (vi)
hence the HCF of 166, 33, 78 is 3
