Flyers is a free Android app developed by MINERVA INC. that aims to help users improve their mental arithmetic skills through flash training. Unlike traditional soroban-style arithmetic training, Flyers trains users to master mental arithmetic through image-based thinking.

Flyers is designed to help users develop their mental arithmetic skills by training their imaginations to visualize numbers and operations. The app is intended for use by members of JSPA, the Japan Soroban Arithmetic Association, and is specifically designed to be used as a supplementary tool for JSPA-affiliated classrooms.

Overall, Flyers is an innovative and engaging app that offers a unique approach to mental arithmetic training. If you're looking to improve your mental arithmetic skills or are interested in exploring the possibilities of image-based thinking, then Flyers is definitely worth checking out.