this is an abacus app .
An abacus is a calculating tool that has been used since ancient times.

It consists of rows of movable beads strung on a wire. They represent digits. One of the two numbers is set up and the beads are manipulated to perform an operation such as addition or even a square or cubic root.

you can choose the style from various beautiful styles.

Image by brgfx on Freepik : https://rb.gy/penfgq