Related Clues:
- Summers
- Early adding devices
- Calculating machines of old
- Calculators' ancestors
- Calculators of old
- Early counters
- Counters with beads
- Rudimentary calculators
- They can always be counted on
- Noisy counters
- Counters in China
- Eastern counters
- Oriental calculators
- On which adders slide to and fro?
- Counting devices