用竖式计算并验算.7.56+27.84= 20.04﹣14.67=
9-4= 10-3= 9-3= 10-7= 7-5= 6-4=
8-5= 8+2= 9-7= 4+4= 10-5= 4+2=
7-4= 9-5= 5+5= 3+3= 7-7= 8-7=
5+3= 5-3= 6-6= 8+1= 9+1= 10-4=
6-5= 10-5= 4+3= 2+2= 2+1= 6-5=