insider.si.edu8 个月
The Abacus and the Numeral Frame
Universities and museums also acquired abaci for their exhibitions. American travelers also acquired them as souvenirs of trips abroad. Some Asian-Americans also used abaci in commerce. Special forms ...
insider.si.edu9 个月
The Abacus and the Numeral Frame
Universities and museums also acquired abaci for their exhibitions. American travelers also acquired them as souvenirs of trips abroad. Some Asian-Americans also used abaci in commerce. Special forms ...