Question

求这5题的简便方法计算！谢谢！

Answer 1

1.25*6.8*0.8=（1.25*0.8）*6.8=1*6.8=6.8
6.6/[15.5-(2.7+1.8)]=6.6/[15.5-4.5]=6.6/11=0.6
6.21/2.3*99+2.7=2.7*99+2.7=2.7*(99+1)=2.7+100=270
6.39+0.65-6.39+0.65=(6.39-6.39)+（0.65+0.65）=0.65+0.65=1.3
2.46*0.4+7.54/2.5=2.46*(1/2.5)+754/2.5=2.46/(2.46*2.5)+7.54/2.5=1*2.46/2.5+7.54/2.5=(2.46+7.54)/2.5=4

Answer 2

1.25×6.8×0.8=（1.25×0.8）×6.8=1×6.8=6.8。
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6.6÷[15.5-（2.7+1.8）]=6.6÷（15.5-4.5）=6.6÷11=0.6。
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6.21÷2.3×99+2.7=2.7×99+2.7=2.7×（99+1）=2.7×100=270
————
6.39+0.65-6.39+0.65=0.65+0.65=1.3
————
2.46×0.4+7.54÷2.5=2.46×0.4+7.54×0.4=（2.46+7.54）×0.4=10×4=40