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0.75*15+4.5*2.5 3.6*31.4+43.9*6.4 简便计算

分类: 作业答案 • 2021-12-19 16:54:19
问题描述：

0.75*15+4.5*2.5 3.6*31.4+43.9*6.4 简便计算

答

=0.75*15+0.25*10*4.5
=0.75*15+0.25*15*3
=15*(0.75+0.75*3)
=15*3
=45

答

0.75*15+4.5*2.5
=(1-0.25)*15+4.5*2.5
=15-2.5*1.5+4.5*2.5
=15+2.5*(4.5-1.5)
=15+7.5
=22.5
3.6*31.4+43.9*6.4
=(10-6.4)*31.4+43.9*6.4
=314+6.4*(43.9-31.4)
=314+6.4*12.5
=314+80
=394

答

0.75*15+4.5*2.5
=45/4+45/4=45/2=22.5
3.6*31.4+43.9*6.4
=（1-6.4）*31.4+43.9*6.4
=31.4-6.4*（43.9-31.4）
=31.4-32/5*5/2
=31.4-16
=15.4

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