二、4以內(nèi)加減珠算
4-3+2+1-2= 2-1+3-2+2= 3-2+1-2+4=
1+ 3-2-1 +3= 4-2+1-2+3= 1+2+1-3+2=
33-11+22= 22+11-33= 11+33-22=
44-22-11= 11+33-44= 22+11+11=
4-3+2+1-2= 2-1+3-2+2= 3-2+1-2+4=
1+ 3-2-1 +3= 4-2+1-2+3= 1+2+1-3+2=
33-11+22= 22+11-33= 11+33-22=
44-22-11= 11+33-44= 22+11+11=