人教版（2012）小学数学一年级下册2 20以内的退位减法十几减9课件(3).ppt

,复习：,9+2=8+6=7+4=6+5=5+9=4+7=8+5=7+5=8+3=9+5=7+8=5+7=,11,14,11,11,14,11,13,12,11,14,15,12,11-（）=10,1,12-（）=10,2,13-（）=10,3,14-（）=10,4,15-（）=10,5,16-（）=10,6,9,8,4,6,5,5,摆一摆，算一算。,10-9=1；1+()=()。,9+()=12；12-9=()。,3,你喜欢哪种方法？还可以怎样计算？,3,3,2,3,6,做减法，想加法。,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,179,129,119,169,139,189,我们一队有12个男生,老师让两个男生之间插进一个女生,1,2,3,4,5,6,7,8,9,10,11,12,答：一共可以插进11个女生。,书本P26,119=2,129=3,139=4,149=5,159=6,169=7,179=8,189=9,119=2129=3139=4149=5159=6169=7179=8189=9,十几减9，是几加1,=,给、或=找个家。12-9411-911+913-313-918-99,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,189,179,129,119,169,139,8,3,7,5,2,4,6,159,149,179,129,119,169,139,189,我们一队有12个男生,老师让两个男生之间插进一个女生,1,2,3,4,5,6,7,8,9,10,11,12,答：一共可