19X19乘法口诀表,快速提高心算速算

乘法口诀初级版1X1 = 11X2=22X2=41X3=32X3=63X3=91X4=42X4=83X4=124X4=161X5=52X5=103X5=154X5=205X5=251X6=62X6=1