Pros
Inexpensive, readily available in many bookstores, have explanations in the workbook
Cons
Explanations are generally procedural rather than deeply conceptual; explanations are worded in a way that may make no sense except to adults who already understand the material. You will have to paraphrase and explain, to a younger kid.
Do you recommend?
For use as a practice workbook or refresher course, yes. Not for a full teaching curriculum.