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1、,十几减几,引 入,引入:,15 9 =,口算,17 9 =,11 9 =,13 9 =,19 9 =,6,8,2,4,10,新授,探究一,探究二,探究一:,探究一,探究二,13 8 =,5,想：8 + ( 5 ) = 13 13 8 = 5,想：10 8 = 2 2 + ( 3 ) = 5,探究一,探究二,探究二:,1、口算。,16 8 =,11 8 =,15 8 =,15 7 =,8,3,7,8,探究一,探究二,11 6 =,16 7 =,11 5 =,16 9 =,5,9,6,7,探究二:,、口答练习。,探究一,探究二,11 6 =,16 7 =,11 5 =,16 9 =,5,9,6,
2、7,探究二:,、口答练习。,探究一,探究二,11 6 =,16 7 =,11 5 =,16 9 =,5,9,6,7,探究二:,、口答练习。,探究一,探究二,11 6 =,16 7 =,11 5 =,16 9 =,5,9,6,7,探究二:,、口答练习。,探究一,探究二,、看谁看得又快又好。,探究二:,12 3 =,13 7 =,12 9 =,13 6 =,9,6,3,7,12 5 =,16 8 =,12 7 =,14 7 =,7,8,5,7,练习,练习一,练习二,练习一,练习二,练习一:,1、看图列式计算。,练习一,练习二,练习一:,1、看图列式计算。,4,8,4,8,6,7,6,7,练习一,练
3、习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,7,4,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,7,9,4,4,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,
4、14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,14 6 =,7,9,6,4,4,8,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,14 6 =,12 6 =,7,9,6,6,4,4,8,6,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,14 6 =,12 6 =,11 8 =,7,9,8,6,6,
5、4,4,3,8,6,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,14 6 =,12 6 =,11 8 =,13 6 =,7,9,8,6,6,6,4,4,3,7,8,6,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,14 6 =,12 6 =,11 8 =,13 6 =,17 9 =,7,9,8,6,6,6,9,4,4,3,7,8,6
6、,8,练习一,练习二,练习一:,2、口算。,11 4 =,13 4 =,11 3 =,13 7 =,14 8 =,12 6 =,17 8 =,14 7 =,11 7 =,13 9 =,14 6 =,12 6 =,11 8 =,13 6 =,17 9 =,14 7 =,7,9,8,6,6,6,9,7,4,4,3,7,8,6,8,7,练习一,练习二,练习二:,练习一,练习二,13只苹果，其中红苹果有8只，绿苹果有几只？,练习二:,练习一,练习二,练习二:,13只苹果，其中红苹果有8只，绿苹果有几只？,练习一,练习二,练习二:,13只苹果，其中红苹果有8只，绿苹果有几只？,13 8 = 5(只),练习一,练习二,练习二:,13只苹果，其中红苹果有8只，绿苹果有几只？,13只苹果，其中绿苹果有5只，红苹果有几只？,13 8 = 5(只),练习一,练习二,练习二:,13只苹果，其中红苹果有8只，绿苹果有几只？,13只苹果，其中绿苹果有5只，红苹果有几只？,13 8 = 5(只),13 5 = 8(只),小结:,今天这节课我们学习了十几减几，知道计算十几减几仍可以采用“想加算减”的方法和“破十减的方法”；还知道了一道减法算式可以改写成另一道对应的减法算式。这样的思想也能帮助我们计算十几减几。,