What is the HCF of 42 77 84?

To find the Highest Common Factor (HCF) of 42, 77, and 84, you first need to find the prime factors of each number. The prime factors of 42 are 2, 3, and 7. The prime factors of 77 are 7 and 11. The prime factors of 84 are 2, 3, and 7. To find the HCF, you need to identify the common prime factors and multiply them together. In this case, the HCF of 42, 77, and 84 is 7.