20个9乘20个4等于多少
问题描述：
20个9乘20个4等于多少
答
44...4(20个)*99...9(20个)=44...4(20个)* [100...0(20个0)-1]
=44..400...0(20个4,20个0)-44...4(20个4)
=44...4355...56(19个4,19个5)