Final answer:
The last digit in the electrode number corresponds to the types of flux coating and provides information about the current and welding positions suitable for the electrode.
Step-by-step explanation:
The last digit in the electrode number designates the types of flux coating. Electrodes are used for arc welding, and the American Welding Society (AWS) has a standardized numbering system where each digit in the electrode classification code represents a specific piece of information about the electrode. The last digit corresponds to the type of coating and current that can be used with the electrode, as well as the suitable welding positions.