Castle Learning Online's products don't come with ready-made answer keys, but they do provide instant feedback and answers once the student has gone through an assignment. They also provide answer hints that guide the student while solving a problem and answer explanations that illustrate the solving process.
Castle Learning's materials provide additional learning reinforcement upon assignment completion, including definitions of terms and explanations of concepts. They provide instant grade reporting, enabling the teacher to spend more time identifying individual student problem areas rather than grading assignments. Castle Learning Online's review and testing tools are designed for elementary- and secondary-school students and cover the major study areas. Students can work on self-generated practice tests and teacher-assigned tasks.