The rules that use the vocabulary item "hundred" are:
<digit-not_zero> hundred
<digit-not_zero> hundred <number>
two hundred fifty
two hundred and fifty
five hundred
two thousand five hundred
twenty five hundred
one hundred thousand
a hundred thousand
two hundred and fifty thousand
two hundred fifty thousand
five hundred thousand
<digit-1_or_2> hundred <tens_number-not_digit_sequence>
<digit-1_or_2> hundred and <tens_number-not_digit_sequence>
<number-not_digit> hundred
hundred