99999×22222+33333×3334= 57+61+65+·······+1093= 巧算,并写出过程.就是99999×22222+33333×3334=的巧算和57+61+65+···········1093=的巧算OK?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/14 06:27:36

99999×22222+33333×3334= 57+61+65+·······+1093= 巧算,并写出过程.就是99999×22222+33333×3334=的巧算和57+61+65+···········1093=的巧算OK?
99999×22222+33333×3334= 57+61+65+·······+1093= 巧算,并写出过程.
就是99999×22222+33333×3334=的巧算和57+61+65+···········1093=的巧算
OK?

99999×22222+33333×3334= 57+61+65+·······+1093= 巧算,并写出过程.就是99999×22222+33333×3334=的巧算和57+61+65+···········1093=的巧算OK?
先算出57+61+65+···········1093共有260项,即共有260个数字相加.
设a1=57,a260=1093
那么,S260={260*(57+1093)*4}/2
=260*1050*2
=546000
99999×22222+33333×3334
=33333×3×22222+33333×3334
=33333×(66666+3334)
=33333×70000
=2333310000

99999×22222+33333×3334=
=33333*3*66666÷3+33333*3334
=33333*66666+33333*3334
=33333*(66666+3334)
=33333*70000
=2333310000
57+61+65+···········1093=
项数(1093-57)/4+1=160

(1093+57)*160/2=92000

不懂