Abacus, amene amati ndi chinthu chachisanu pa zinthu zonse zotulukira m’mbiri ya dziko lathu, si chida chogwiritsiridwa ntchito kwambiri cha masamu komanso chida chophunzirira, chophunzitsira, ndi zoseŵeretsa zophunzitsira. Itha kugwiritsidwa ntchito pophunzitsa ana kukulitsa luso la ana kuchokera pamalingaliro azithunzi...
Werengani zambiri