What is the hcf of 126 196 378?

To find the highest common factor (HCF) of 126, 196, and 378, we first need to find the prime factors of each number. The prime factors of 126 are 2 x 3 x 3 x 7, the prime factors of 196 are 2 x 2 x 7 x 7, and the prime factors of 378 are 2 x 3 x 3 x 3 x 7. To find the HCF, we look for the common prime factors among the numbers, which are 2 and 7. Multiplying these common factors gives us the HCF, which is 14.