In terminal digit filing order, which digits are typically used as the primary sort key?

• A. The first two digits
• B. The middle digits
• C. The last two digits
• D. The entire number

Answer: (C)

The last two digits are used as the primary sort key. In terminal digit filing, records are grouped first by those ending digits, which creates 100 possible primary groups (00–99) and helps distribute workload evenly. If two records share the same ending two digits, you then use the digits before them as secondary keys to determine the order, continuing as needed for finer sorting. This approach keeps similar-endings together and makes it quicker to locate or file records, rather than sorting by the start of the number or by the entire number all at once. For example, numbers ending in 45 go into the same primary bucket, and within that bucket you compare the preceding digits to decide order.