| Answer | Crossword Clue |
|---|---|
| ABACI | Calculators of yore |
| ABACI | Calculators of old |
| ABACI | Calculators of sorts |
| SLIDERULES | Forerunners of pocket calculators |
| RETROREFLECTORS | Calculators of distance from earth |
| CASIO | Maker of watches and calculators |
| CASIO | Japanese maker of watches and calculators |
