Do not skip the "Exercise 1" (basic recall). Japanese students do 10-20 basic problems before touching a word problem. Use the PDF's search function to find the answer section (usually in the back 10 pages). If your PDF lacks answers, buy a separate "解答" (Kaitou) booklet.
Japan is renowned for its rigorous education system, with a particular emphasis on science, technology, engineering, and mathematics (STEM) fields. Mathematics education in Japanese high schools plays a crucial role in preparing students for a competitive academic environment and, eventually, for careers that require a strong foundation in analytical and problem-solving skills. Japanese High School Math Textbook Pdf
The textbooks often spiral back to previously learned material. Do not skip the "Exercise 1" (basic recall)