用简便方法计算 1999²+3998+1 11²+13*66+39²
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/06/04 04:15:00
用简便方法计算 1999²+3998+1 11²+13*66+39²
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
=1999²+2*1999*1+1
=(1999+1)²
=2000²
=4000000
11²+13*66+39²
=11²+2*11*39+39²
=(11+39)²
=50²
=2500