几道小学六年级奥数题(简便运算)1/1*3+1/3*5+1/5*7+……+1/47*49== 1/2*5+1/3*5+1/8*11+……+1/20*23== 3/4+7/12-9/20+11/30-13/42== 2002/1*3+2002/3*5+2002/5*7+2002/7*9+2002/9*11==最好写上过程,解题思路.
来源:学生作业帮助网 编辑:作业帮 时间:2024/11/08 17:13:38
几道小学六年级奥数题(简便运算)1/1*3+1/3*5+1/5*7+……+1/47*49== 1/2*5+1/3*5+1/8*11+……+1/20*23== 3/4+7/12-9/20+11/30-13/42== 2002/1*3+2002/3*5+2002/5*7+2002/7*9+2002/9*11==最好写上过程,解题思路.
几道小学六年级奥数题(简便运算)
1/1*3+1/3*5+1/5*7+……+1/47*49
=
=
1/2*5+1/3*5+1/8*11+……+1/20*23
=
=
3/4+7/12-9/20+11/30-13/42
=
=
2002/1*3+2002/3*5+2002/5*7+2002/7*9+2002/9*11
=
=
最好写上过程,解题思路.
几道小学六年级奥数题(简便运算)1/1*3+1/3*5+1/5*7+……+1/47*49== 1/2*5+1/3*5+1/8*11+……+1/20*23== 3/4+7/12-9/20+11/30-13/42== 2002/1*3+2002/3*5+2002/5*7+2002/7*9+2002/9*11==最好写上过程,解题思路.
1/1*3+1/3*5+1/5*7+……+1/47*49
= 1/2(1-1/3)+.1/2(1/47-1/49)
= 1/2(1-1/3+1/3-1/5+.+1/47-1/49)
=24/49
1/2*5+1/3*5+1/8*11+……+1/20*23
=
=
3/4+7/12-9/20+11/30-13/42
=(1-1/4+1/4+1/3-1/4-1/5+1/5+1/6-1/6-1/7)
= 1+1/3-1/4-1/7
=79/84
2002/1*3+2002/3*5+2002/5*7+2002/7*9+2002/9*11
=2002(1/1*3+1/3*5+...+1/9*11)
=2002[1/2(1-1/3)+1/2(1/3-1/5)+...+1/2(1/9-1/11)
=2002*5/11
=910