What is the HCF of 60 and 45?

To find the HCF of two numbers you first need to express them as the product of their prime factors. In this case you'd get:

45 = 3x3x5

60 = 2x2x3x5

The next step is to identify any common prime factors. In this case both numbers have a 3 and a 5 as a prime factor. Multiplying these together gives:

3x5 = 15

And so 15 is the HCF of 45 and 60.