The rules that use the category "<digit-1>" are:

<degree_number-180-digit_sequence>

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

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

<digit-1> <digit-8> <digit-0>

<digit-1> <digit_zero_to_seven> <digit>

<degree_number-180-digit_sequence-sing>

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

<degree_number-180-not_digit_sequence-sing>

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

<degree_number-180-digit_sequence-pl>

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

<digit-1> <digit-8> <digit-0>

<digit-1> <digit_zero_to_seven> <digit>