算盘 (suàn pán): abacus; plan; scheme

Grandpa took an old abacus out of the drawer and taught me step by step how to move the beads to do calculations.

Although everyone uses calculators now, the owner of this old shop still prefers to use an abacus to calculate the daily revenue.

An abacus from the Ming Dynasty is displayed in the museum; the guide said it was an essential calculating tool for merchants at that time.

He learned to use an abacus from his father since childhood, and his fingers moved so skillfully that it was dazzling to watch.