10﹣0.9= 28+82= 20×5%= +×0=
4.8÷0.8= += ×= 1÷-1=
验算
﹣ = + = 0.25+ = ﹣ = 4×2.5=
0×98.56= 45×11= 0.85﹣15%= 0.65×101﹣0.65=
×10÷ ×10=