Key to Fractions Answers and Notes: Books 1-4 Do you have students who have never mastered fraction concepts or who need a good review? Key to Fractions covers all topics from basic concepts to mixed numbers and is written with secondary students in mind. Minimal reading is required, so students can easily work independently or in small groups. These self-paced, self-guided workbooks motivate students to succeed. This is the Answers and Notes book but it does include the complete text of all 4 of the student Key to Fractions books along with some teaching tips.