3.89×3.89-4.89×2.89用简便运算怎么做?

2025-04-28 05:38:29
推荐回答(1个)
回答1:

3.89×3.89-4.89×2.89
=3.89x3.89-(3.89+1)x(3.89-1)
=3.89x3.89-(3.89x3.89-1x1)
=1