苏教版数学一年级下册《整十数加、减整十数》2.ppt
整十数加、减整十数,苏教版一年级数学下册,执教者:覃小菊,我 会 算,3+2=2+7=6-3=9-4=5+1=7-2=5+3=8-5=7-4=2+5=8-2=5+4=,5,3,6,8,9,5,5,3,3,7,6,9,我 会 想,80里面有()个10;50里面有5个();()里面有7个十;6个十是()。30里面有()个十。,8,十,70,60,3,拆数游戏,把文字描述的数写在括号里。7个十();3个十();4个十();10个十()。,70,30,40,100,30+20=,?,点击头像,3020?,50,十个十个地数,30,40,50。,3个十,5个十,3020?,2个十,50,3020?,0,0,3,0,2,5,325,40+20=30+50=60+10=20+70=,算一算,说一说你是怎么想的?,4个十,2个十,6个十,60,80,70,90,50 20=,?,5个十,3个十,5020?,2个十,30,5020?,0,0,5,0,2,3,也可以这样算:,50,40,90,40,50,90,90,40,50,90,50,40,3+2=()30+20=(),6 4=()60-40=(),5,50,2,20,观察上面两组算式,你能发现什么呢?,对比练习,智慧城堡,加油啊!,20,50,60,70,40,30,做加法,试一试,你准行!,50,60,70,80,90,80,50,60,70,40,30,做减法,试一试,你准行!,50,40,30,20,10,60,10,+30,70,40,+60,80,40,+30,50,+10,+60,50,80,10,70,30,40,70,20,30,90,80-50,70+20,20+30,10+80,90-20,30+40,60-40,70-30,60-20,考 考 你,谢谢!,