わたしの: Japanese math, one problem at a time

Field notes

The homepage presents a dated featured puzzle and an archive organized by topic, including geometry, area, work-rate problems, and train timing. Individual entries pair prompts with printable PDFs, while selected solutions link to videos narrated by one of three named teaching characters. The site says its problems are remade using borrowed approaches; it also describes the teachers as explanatory characters who may change, and says an app for additional explanations is still being prepared.