①4:5=x:25
②1+4x=6.7
③3x﹣60%x=4.32
④:3
①(+-)÷
②12-(1+2)
③5÷[(+)×]
④2.5×3.2×0.125
⑤0.125×+×8.25+12.5%
⑥÷﹣