Kids Study Lab Expanded: 6,168 Practice Questions Across Five Middle-School Subjects, and 2,107 "Learn More" Columns with Cited Sources, Now Open

NPO Digital Kodomo BASE has expanded its learning site "Kids Study Lab" (https://digitalkodomo.jp/kids-study/) (Japanese-only content) with practice question sets covering 139 chapters and a total of 6,168 questions across five middle-school subjects, and 2,107 "Learn More" columns that go one step beyond the textbook. Every practice page lets students check their answers on the spot, and each column is backed by citations to trustworthy sources such as ministries, public institutions, universities, and academic societies — connecting classroom content to real-world topics, daily life, and current affairs.

1. Practice Questions: 139 Chapters, 6,168 Items, Five Subjects

For each grade and subject in middle school (Grades 7–9), practice and review questions are now available chapter by chapter. From the new Practice Top page (https://digitalkodomo.jp/kids-study/problems.html), students can reach every practice set in one or two clicks by grade and subject. Each practice page reveals answers and short explanations in place, so it can be used repeatedly for self-study or test preparation.

Subject	Questions	Chapters
Math	468	25
Science	600	12
English	1,800	36
Japanese (Kokugo)	1,400	28
Social Studies (History, Geography, Civics)	1,900	38
Total	6,168	139

2. "Learn More" Columns: 2,107 Items with Cited Sources

Across all 405 explanatory units, four to six "Learn More" items per unit have been added, expanding on the textbook with developmental topics, real-life examples, and current affairs. History chapters reference national archives and museum commentary; science chapters bring in observational data from the Japan Meteorological Agency and JAXA; geography chapters draw on the Geospatial Information Authority of Japan and the Japan Tourism Agency. Each column is designed so that students can step from the textbook into the real world around it.

Sources are limited to public and trustworthy ones: government and ministry sites (Agency for Cultural Affairs, MEXT, MIC, GSI, JMA, JTA, JAXA, NHK, JICA, etc.), universities and academic societies, and well-established encyclopedias and dictionaries. The columns are not the textbook itself, but topics anchored to the textbook with citations and presented as developmental and real-life reading.

3. Sample Pages

• Practice Top: https://digitalkodomo.jp/kids-study/problems.html
• Social Studies (History, Ch. 2 — Taika Reform): https://digitalkodomo.jp/kids-study/history-02-02-taika.html
• Science (Grade 7 — Plant Classification): https://digitalkodomo.jp/kids-study/junior1-science-01-05-plant-classification.html
• Math (Grade 7 — Prime Factorization): https://digitalkodomo.jp/kids-study/junior1-math-00-01-prime-factorization.html

4. Existing Explanations Fully Reviewed and Revised

Alongside this expansion, every previously published explanatory article has been re-checked against primary textbook sources and fact-verified. Dates, names, and terminology have been aligned with current textbook usage, and loosely supported wording has been tightened. The goal is to keep the site reliable for daily learning.

5. What's Next

We plan to keep growing the question bank, add "topic-only" access (for example, only the questions in a specific genre), and introduce cross-grade comprehension checks. Students will be able to revisit weak areas across grades even after moving up a year.

6. Mission

Kids Study Lab is published free of charge so that children with limited access to learning at home or at school can still reach quality materials. It can serve as a supplement to school textbooks or as a self-study resource at home. The site is operated entirely with the support of donors and supporters; donations are received at /donate_en.html.