如题所述
(45+5)(45-5)+25=50X40+25=2025.通用做法:Y5XY5=(Y+5)(Y-5)+25
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第1个回答 2016-11-10
45X45
=(50-5)X(50-5)
=50X50-50X5-5X50+5X5
=2500-250-250+25
=2025本回答被网友采纳
=(50-5)X(50-5)
=50X50-50X5-5X50+5X5
=2500-250-250+25
=2025本回答被网友采纳