不计算积,试比较12489×12356与12359×12486的大小
口算= = = ×9= ÷12== = = 7.8×9+7.8= ×0=24×()= 12×=
直接写出下面各题的计算结果:(1)= (2)= (3)1×= (4)1= (5)÷5﹣÷5=(6)= (7)×5= (8)÷3= (9)= (10)×9+=
+= 18×= ﹣= 12÷= ×=÷10= 1﹣= ×= += ÷=
直接写得数:= = 24×= = = == 80×1.4= 100×= 240÷0.5= 0.6×0.6= 300×40%=
口算题.= 6=××7= 120×5%=