直接写得数.13×3= 12×4= 15×5=32×3= 130×3= 120×4=150×5= 320×3= 16×3=29×3= 4×17= 4×19=160×3= 290×3= 4×170=40×19=
用简便方法计算下列各题.(1)1240×3.4+1.24×2300+12.4×430 (2)4.05+4.08+4.11+…+7.02.
2011÷125.
简便计算375﹣98500﹣56﹣4489+233+511+377+567+123.
①1993+1994+1995+1996+1997+1998+1999+2000=②(0.75×42.7+57.3﹣0.573×25)÷3×7972=
计算.0.25×0.03×4 13×3.89+0.13×100+1.3×51.1 10.1×87.