整十数加、减整十数,30座,40座,40 + 30 = ( 个 ),?,70 30 =,?,你是怎样想的？,试一试,50,40,90,40,50,90,90,40,50,90,50,40,想想做做,对比练习,3 + 2 =（ ）30 + 20 =（ ）,5 1 =（ ）5010 =（ ）,9 3 +2 =（ ）9030 +20=（ ）,5,50,4,40,8,80,2 + 3 + 4 = ( )20+30+40=（ ）,9,90,60,10,+30,70,40,+60,80,40,+20,50,+30,+6,50,80,10,70,30,40,60,10,40,46,想想做做,20 + 40= 7010= 10 + 80 + 6 =9070= 30 + 30= 30 + 70=60 + 30= 60 - 30= 80 50=,60,20,90,60,60,96,90,100,30,口算练习,80-50,70+20,20+30,10+80,90-20,30+40,60-40,70-30,60-20,考 考 你,20+30 100-60 40-10 30-0 0+40 70-20 90-40 30+10 20+30 50-10 40+30 70-30 10+30 60-40,得数是40的路才是回家的路,
