0.0938×6210-[210×0.006 8+(13.9×15.7+0.63×278-1.57×76)÷15]=________.
562.8
分析:按照有理數(shù)混合運算的順序,先乘除后加減,有括號的先算括號里面的,計算過程中注意正負符號的變化.
解答:方法(1)原式=0.0938×6210-[210×0.006 8+(218.23+175.14-119.32)÷15],
=0.0938×6210-[210×0.006 8+(218.23+175.14-119.32)÷15],
=0.0938×6210-(210×0.006 8+274.05÷15),
=0.0938×6210-(1.428+18.27),
=582.498-19.698,
=562.8.
方法(2)原式=0.0938×6210-[210×0.0068+(13.9×15.7-15.7×7.6+6.3×27.8)÷15]
=0.0938×6210-[210×0.0068+(6.3×15.7+6.3×27.8)÷15]
=0.0938×6210-[210×0.0068+6.3×43.5÷15]
=0.0938×6210-[2.1×0.68+2.1×8.7]
=9.38×62.1-2.1×9.38
=9.38×60
=562.8.
點評:本題考查的是有理數(shù)的運算能力,運算較復雜,必須理清運算順序方可正確運算.