用简便方法计算 1999²+3998+1 11²+13*66+39²

来源：学生作业学帮网编辑：学帮网时间：2024/06/25 01:53:26

1999²+3998+1
=1999²+2*1999*1+1
=(1999+1)²
=2000²
=4000000
11²+13*66+39²
=11²+2*11*39+39²
=(11+39)²
=50²
=2500