=800-800
=0
=2.1÷2.1
=1
10﹣6.8= ﹣ = 35×1%= 1.25×24= 5× ÷5× =
0.42= 10÷0.02= 5a×7a= 1÷3= 1﹣1÷6=
0.25×8= 50%×0.4= 7÷7%= 23=