The rules that use the category "<digit>" are:

<second_setting>

<minutes-pl> point <digit> <digit> <time_interval_unit-second-pl>

<minutes-sing> point <digit> <digit> <time_interval_unit-second-sing>

<degree_number-not_initial_zero-90-pl>

<digit_one_to_eight> <digit>

<bearing_number-pl>

three <up_to_six> <digit>

<up_to_two_digits-sing>

<digit> <digit-sing>

<degree_number-180-pl>

<digit> <digit>

<digit-0> <digit_not_one> <digit>

<digit-0-pl> <digit-1> <digit>

<digit-1> <digit_zero_to_seven> <digit>

oh_one <digit>

<up_to_two_digits-pl>

<digit> <digit-pl>

<up_to_two_digits>

<digit> <digit>

<ship_speed>

speed <digit_one_to_five> <digit>

<bearing_number-three_dig-pl>

three <up_to_six> <digit>

<degree_number-360-pl>

<digit-0> <digit_not_one> <digit>

<digit-0-pl> <digit-1> <digit>

<digit-1_or_2> <digit> <digit>

<digit-3> <digit_zero_to_five> <digit>

oh_one <digit>

<up_to_four_digits>

<digit> thousand

<unit_call_sign>

<any_letter> <digit> <any_letter>

battalion <digit-not_zero> <digit>

battalion <digit-not_zero> <digit> <digit>

battalion <digit-not_zero> <digit> <digit> <digit>

<battle_position>

<battle_position_noun> <digit> <digit> <digit>

<minutes>

<digit_zero_to_five> <digit>

<tens_number-pl>

<digit-not_zero> <digit>

<bearing_number-three_dig>

three <up_to_six> <digit>

<degree_setting_in_tens-360>

<digit-1_or_2> <digit>

<digit-1_or_2> <digit> <answer>

<decimal>

point <digit>

<number>

<digit> <digit>

<tens_number>

<digit-not_zero> <digit>

<minutes-pl>

<digit_zero_to_five> <digit>

<loadable_item_callsign>

pallet <digit> <digit> <digit>

<ordered_distance>

distance <digit-1_or_2> <digit>

range <digit-not_zero> <digit>

<degree_number-360-digit_sequence-pl>

<digit-0> <digit_not_one> <digit>

<digit-0-pl> <digit-1> <digit>

<digit-1_or_2> <digit> <digit>

<digit-3> <digit_zero_to_five> <digit>

oh_one <digit>

<bearing_number>

three <up_to_six> <digit>

<track_number>

<digit> <digit> <digit> <digit>

l <digit> <digit> <digit> <digit>

lima <digit> <digit> <digit> <digit>

<coordinate_nums>

<digit> <digit> <digit> <digit>

<digit> <digit> <digit> <digit> <digit> <digit>

<digit> <digit> <digit> <digit> <digit> <digit> <digit> <digit>

<two_digits>

<digit> <digit>

<minutes-sing>

<digit_zero_to_five> <digit>