400﹣98=
算一算.+= 1﹣= ﹣= += ﹣= +=
修一条公路,第一队修了总长的,第二队修了总长的,两队共修了这条公路的几分之几?
计算下面各题.= = = ﹣= 1﹣=﹣= = ﹣= =
看谁算得又对又快.= = == = =.