计算:(5+2)+(5+2×2)+(5+2×3)+.+(5+2×90)的过程.

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/08 17:18:57
计算:(5+2)+(5+2×2)+(5+2×3)+.+(5+2×90)的过程.

计算:(5+2)+(5+2×2)+(5+2×3)+.+(5+2×90)的过程.
计算:(5+2)+(5+2×2)+(5+2×3)+.+(5+2×90)的过程.

计算:(5+2)+(5+2×2)+(5+2×3)+.+(5+2×90)的过程.
一共是90个括号 你把括号去掉
那就是90*5加上2*1+2*2+2*3+.+2*90
可以简写成2*(1+2+3+.+90)+90*5=2*4050+90*5=8550