Study River makes printable A4 practice sheets — one page that fits today. You decide what, how much and how hard, by talking to your AI or by tapping a few buttons. It's free.
MathAddition to long division, decimals, fractions, 100-square grids, integers and equations — 42 steps
Logic8 puzzle types × 3 levels: grids, rotation, odd one out, paper folding, cube nets and more
MazesSmall, medium and large, with the solution on the answer page
Picture words2,016 illustrated words to trace or write — in English, Spanish or Portuguese
JapaneseHiragana, katakana and kanji tracing, and vertical-text reading
English writingJapanese → English sentence practice and fill-in-the-blank, A1 to C2
For anyone, at any time
Study River is about lifelong learning. When, where and what you learn is up to you. A simple math sheet can be a warm-up for an adult, a challenge for a child, or a relaxing puzzle at any age. We describe sheets by content and difficulty — never by age.
How a sheet works
Page 1 is the problems, page 2 is the answers.
Black and light gray only, made for home printers (picture words use colour illustrations, which print fine in black and white).
Each sheet comes from a short spec and a number called a seed. The same spec and seed always make exactly the same page — so checking answers only means noting which numbers went wrong.
If the content doesn't fit on one A4 page, Study River tells you instead of quietly cutting it.
Your record stays with you
Results you record in the web app are saved only in your browser on your device — nothing is sent to our servers, and there is no account. You can export everything as a JSON file at any time and ask any AI to read it and plan the next step.
Two ways to use it
With your AI — add the Study River skill to Claude, or connect Study River to an AI agent (MCP), and just ask for the sheet you want.
Web app — pick skills and minutes on screen and download the PDF. No AI needed.
Free, and how it is funded
Making, printing and recording sheets is free. To keep it free, the website may show ads on its web pages (never on the printed sheets). You can also support us with a tip on Ko-fi. Some ready-made templates and guides are sold separately.
Who makes it
Study River is planned and run by Eidendo Inc., a small company in Japan. We also publish learning videos on YouTube (Study River Math, Logic, PD, Stat and more). Questions and feedback: study@eidendo.co.jp.