(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)要求简便运算.
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/05 05:33:28
(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)要求简便运算.
(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
要求简便运算.
(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)要求简便运算.
(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
=(1/2+1/4)+(1/7+1/14+1/28)-(1/3+1/5+1/10+1/15+1/30)
=3/4+1/4-11/15
=4/15
(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
= 1/2 - 1/3 + 1/4 + (1/7 + 1/14 + 1/28) - (1/5 + 1/10 + 1/15 + 1/30)
= 1/2 - 1/3 + 1/4 + 7/28 - 12/30
= 1/2 - 1/3 + 1/4 + 1/4 - 2/5
= 1 - 1/3 - 2/5
= 2/3 - 2/5
= 4/15
原式=(1/2+1/4+1/7+1/14+1/28)-(1/3+1/5+1/10+1/15+1/30)
=28/28-22/30=1-22/30=8/30=4/15
=1/2+1/4+1/7+1/14+1/28-1/3-1/5-1/10-1/15-1/30
=(1/2+1/4+1/7+1/14+1/28)-(1/3+1/5+1/10+1/15+1/30)
=28/28-22/30
=1-11/15
=4/15
好久没算数了,有点晕。哈哈