简便计算 一定要有过程.11
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:2024/07/31 17:53:42
简便计算 一定要有过程.11
1998/(1×2)+ 1998/(2×3)+ 1998/(3×4)+ 1998/(4×5)+ 1998/(5×6)
1998/(1×2)+ 1998/(2×3)+ 1998/(3×4)+ 1998/(4×5)+ 1998/(5×6)
![简便计算 一定要有过程.11](/uploads/image/z/17203044-12-4.jpg?t=%E7%AE%80%E4%BE%BF%E8%AE%A1%E7%AE%97+%E4%B8%80%E5%AE%9A%E8%A6%81%E6%9C%89%E8%BF%87%E7%A8%8B.11)
1998/(1×2)+ 1998/(2×3)+ 1998/(3×4)+ 1998/(4×5)+ 1998/(5×6)
= 1998×(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6)
= 1998×5/6
= 1998-1998×1/6
= 1665
= 1998×(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6)
= 1998×5/6
= 1998-1998×1/6
= 1665