: The opening chapters dive deep into polynomial expansion, factorization, and complex real numbers. Quadratic Functions : Students master the "discriminant" (
Amazon.co.jp (Japan) sells many of these textbooks as Kindle eBooks. You can buy them digitally, download them, and (using conversion tools) save a personal copy as a PDF. Expect to pay ¥800–¥1,500 ($6–$10 USD) per book. Japanese High School Math Textbook Pdf
For those specifically looking for the academic rigor of Japanese math in English, the has published translated versions of the standard Tokyo Shoseki textbooks Japanese High School Math Textbook — Sample Content