Mechanical arithmetic aids (5)
I believe the answer is:
abaci
(Other definitions for abaci that I've seen before include "Counting devices" , "frames" , "Early computers" , "They can be counted on" , "help for summer" .)
I believe the answer is:
abaci
(Other definitions for abaci that I've seen before include "Counting devices" , "frames" , "Early computers" , "They can be counted on" , "help for summer" .)