LC II question re:lesson 20

[mom23]

Lesson 20 for Latina Christiana II (2nd edition) has a question in the grammar section regarding declining adjectives and nouns. Maybe I missed this earlier, but the answers in the teacher's manual don't seem to agree with what was taught in LC I - adjectives must agree with the noun they modify in case, gender and number. I am referring to the declension of "bad leader" and "good law". For example, why isn't the dative case of bad leader duci mali instead of duci malo as the teacher's manual states and the ablative case of good law lege bone instead of lege bona?

[Anonymous]

malus and bonus decline like first and second declension nouns; the dative singular masculine form of malus is malo, therefore duci malo; likewise, the ablative singular feminine of bonus is bona, therefore lege bona. bone is not a valid form.