数学-乘法的初步认识ppt课件.ppt
2-1-,2+2+2+2+2+2,6+6,4+4+4,3+3+3+3,:()(),4,2,2+2+2+2=8(),:,4+4+4+4+4+4=24(),:()(),6,4,:,3+3+3=9(),:()(),3,3,:,(),:,2+2+2+2=8(),4+4+4+4+4+4=24(),3+3+3=9(),2+1+3=6(),(),(),2+2+2+2=8,4+4+4+4+4+4=24,3+3+3=9:,2+2+2+2=8,4+4+4+4+4+4=24,3+3+3=9,24=842=8:,24=8:42=8:,:,:,46=2464=24,:,33=9,3 4 4 3.,4+4+4=12,3+3+3+3=12,:4 3=12 3 4=12,:,继续动脑筋,3+3+3+3,5+5+5,2+2+2+2+2,7+7+7+7+7,75,34,53,25,2+2+2=6,23=6 32=6,4,3,4,3,3,4,3,6,3,6,6,3,.,1.5+5 10.(),2.2 6 2 6.(),3.5 3 8.(),4.2+4+5.(),4100,0.5 20,