99x(100—1)x99 用简便方法计算。

2024-11-26 03:20:41
推荐回答(2个)
回答1:

要懂得会还原,99变成100
99x(100—1)x99
=99x99x99
=(100-1)(100-1)(100-1)
=100x100x100-3x100x100+3x100-1
=1000000-30000+300-1
= 970299

回答2:

99x(100—1)x99
=99x99x99
=(100-1)(100-1)(100-1)
=100x100x100-3x100x100+3x100-1
=1000000-30000+300-1
= 970299