Terminal digit filing is a filing system used to organize numerical records in numerical order. In this system, the last digit of each record is used as the filing criterion. To convert straight numerical to terminal digit filing, you must first identify the last digit in each numerical record. Then, you must organize the records in numerical order based on the last digit. For example, if the numerical records are 12, 21, 17, and 31, the last digits are 2, 1, 7, and 1, respectively. The records should be organized in numerical order based on the last digit to be 1, 1, 2, 7 (21, 31, 12, 17).