To find the highest common factor (HCF) using factors, what is the first step?

To determine the highest common factor (HCF) using factors, the first step is to list the factors of both numbers. This involves identifying all the integers that can divide each number without leaving a remainder. Once the factors are listed, it becomes straightforward to identify the common factors between the two sets and subsequently determine the highest among them, which is the HCF.

The other options do not align with the HCF calculation process. Identifying multiples is a related concept but does not directly lead to the HCF; instead, it focuses on the least common multiple (LCM). Multiplying the numbers together does not provide any useful information regarding their factors or commonality. Finding the average also does not contribute to determining common factors; it is unrelated to the process required for HCF calculation. By starting with the factors, you create a clear path to finding the HCF efficiently.