Written Arithmetic Calculator "PaperCalc"

What is this?

PaperCalc is a JavaScript program that automatically demonstrates step-by-step written arithmetic — addition, subtraction, multiplication, and division.

It is a web-based learning tool aimed at elementary school students (grade 3 and above).

• Demo: https://katahiromz.github.io/PaperCalc/

Development Setup

Requirements

• Node.js (includes npm)

Install dependencies

npm install

Build

Compile JavaScript files to dist/ and copy static assets:

npm run build

Watch mode

Recompile automatically on file changes (JS/TS only; re-run build for asset changes):

npm run watch

Type-check without emitting output

npm run typecheck

Serve locally

After building, serve the dist/ directory with any static file server. For example:

# Using Python (built-in)
python3 -m http.server 8080 --directory dist

# Or using Node.js npx
npx serve dist

Then open http://localhost:8080 in your browser.

License

• MIT

Contact

• Katayama Hirofumi MZ katayama.hirofumi.mz@gmail.com