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巧算:(5.4*3.8)-(6.5*4.4)+(2.7*5.4)199.4*19.93-199.3*5.4注释:*代表乘号

题目详情
巧算:(5.4*3.8)-(6.5*4.4)+(2.7*5.4)
199.4*19.93 - 199.3*5.4
注释:*代表乘号
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答案和解析
(5.4*3.8)-(6.5*4.4)+(2.7*5.4)
=:(5.4*3.8)+(2.7*5.4)
-(6.5*4.4)
=5.4*(3.8+2.7)-(6.5*4.4)
=(5.4*6.5)-(6.5*4.4)
=6.5*(5.4-4.4)
=6.5*1
=6.5
199.4*19.93 - 199.3*5.4
=19.94*199.3-199.3*5.4
=199.3(19.94-5.4)