-= += ×5÷×5= 4÷0.01×0.1=
4÷-1= 100×9.8+0.2= 15.4﹣(5.4﹣4.5)= 0.15:0.3=
①×+×
②×(2÷)
③÷(1﹣(+)]
④12.5×0.97×0.8
⑤6000÷(75﹣60)+20
⑥(+﹣)×48
470cm3=dm3=L 0.26km2=公顷