10以内混合加减法9+1-9= 7-4+5= 8-1+2= 1+6-6=5-0-3= 0+0+0= 9-0-7= 4-4+5=2+2+1= 7-2-5= 2+1+4= 2+5+2=6-2-1= 6+1