Question: Which ‘A’ is a calculating frame with sliding balls on wires?
Answer: Abacus Calculation; Russian abacus; Abaci; Nepohualtzintzin; Abacus (Aztec); Cranmer abacus; Abacuses; Counting frame; Abacus; Abacist; Abacus (mathematics); Abacists; Bead frame; Abacus arithmetic; AbacuS; Counting frames; Abbacus; Reckoning frame