The N3 Dokkai book relies heavily on referencing the "Answer Key and Explanations" booklet. Flipping between pages in a PDF is cumbersome compared to having the physical answer key side-by-side.

: Unlike many books that only offer practice questions, this one teaches

Strategies for "Information Retrieval" (finding specific facts) versus "General Understanding" (grasping the author's intent). The Problem with "Free PDF" Downloads