Definitions:

1. A calculating instrument that uses beads that slide along a series of wires or rods set in a frame to represent the decimal places. noun
   • In ancient China, the abacus was an essential tool for merchants to calculate profits and loses.
2. An instrument for performing calculations by sliding counters along rods or in grooves. NOUN
   • Using the abacus, students can develop a deeper understanding of arithmetic principles.

Synonyms:

• adding machine
• calculating frame
• calculator