HCF of 12, 18, 42, Option : A. 123 B. 60 C. 12 D. 6
Write prime factors
- 12 = 2 × 2 × 3 = 2² × 3¹
- 18 = 2 × 3 × 3 = 2¹ × 3²
- 42 = 2 × 3 × 7 = 2¹ × 3¹ × 7¹
Take common prime factors with smallest powers
Common primes = 2 and 3
→ HCF = 2¹ × 3¹ = 6
HCF of 12, 18, and 42 = 6