if something zero something else then that something contributes to that something else
zero is not lower_number_than_one. zero is digit. zero is not digit. zero is not set_containing_one_element. change is when_one_thing_becomes_another_thing. zero is set_containing_one_element. zero is not numerical_quantity. change is not when_one_thing_becomes_another_thing. zero is lower_number_than_one. everything is not one_thing.