课件15张PPT。新授课件苏教版数学一年级下册第四单元整十数加、减整十数导入新课734836409040座30座70探究新知70座30座探究新知40探究新知1.9040509050904050巩固练习5502.440990880巩固练习3.5080107030巩固练习3.4060104046巩固练习4.60+30 =9090-70 =2020+40 =6060-20 =4030+30 =6070-10 =6080-50 +7 =3710+80 +6 =9630+70-40 =60巩固练习5.202040+(个)巩固练习巩固练习