十 几 减 几,苏教版一年级数学下册,?,教学目标,掌握十几减几的计算方法。能理解十几减几退位减法的算理,能正确地进行计算。进一步感知加减法算式之间的联系,促进计算能力的提高。,13 15 ( )10 ( ) 5 ( ) 7 10,14 16 ( )( ) 10 6 ( ) 10 2,3,10,17,4,10,12,?,10-8= 10-9= 10-6= 10-5= 13-2= 17-7= 11-1= 12-2= 10-7=15-7=13-3= 18-8=,口算,有13个气球。,布置房间要用6个。,还剩多少个,?,13-6=?,15 6 =13 5 =11 4 =,?,14 5 = 15 6 = 11 1 = 13 4 = 16 7 = 15 6= 12 3 = 17 8= 13 5 =,用你自己喜欢的方法算一算,3 = 4 =11 5 = 6 =,6 = 5 =12 4 = 3 =,8,7,6,5,6,7,8,9,?,15 9 = 5 + 9 = 7 + 9 = 13 8 = 7 + 5= 18 9 = 16 8 = 2 + 9 =17 9 = 11 7 = 12 9 = 11 8 =,( 注 意 +、 号 ),( ) ( )= 6,?,今天,你又有哪些收获?,