初一数学题:|1/3-1/2|+|1/4-1/3|+|1/5+1/4|+.+|1/100-1/99|=?有谁能解急
初一数学题:|1/3-1/2|+|1/4-1/3|+|1/5+1/4|+.+|1/100-1/99|=?有谁能解急
1/2<1,1/2-1<0,所以 |1/2-1|=1-1/2
同理
1/3<1/2,|1/3-1/2|=1/2-1/3
……
|1/100-1/99|=1/99-1/100
所以原式=1/2-1/3+1/3-1/4+……+1/99-1/100
中间正负抵消
=1/2-1/100
=49/100
数学题，要答案，速度。 |1/3-1/4|+|1/4-1/5|+.+|1/19-1/20|=
|1/3-1/4|+|1/4-1/5|+......+|1/19-1/20|
=(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+...+(1/19-1/20)
=1/3-1/4+1/4-1/5+1/5-1/6+...1/19-1/20
=1/3-1/20
=17/60
谁能解这道数学题：1/（1*2*3）+1/（2*3*4）+1/（3*4*5）+.1/（26*27*28）=？
1/(1*2*3)=1/2*[1/1*2-1/2*3]=1/2*[(1/1-1/2)-(1/2-1/3)]=1/2*[1/1-2/2+1/3]
1/(2*3*4)=1/2*[1/2*3-1/3*4]=1/2*[(1/2-1/3)-(1/3-1/4)]=1/2*[1/2-2/3+1/4]
1/(3*4*5)=1/2*[1/3*4-1/4*5]=1/2*[(1/3-1/4)-(1/4-1/5)]=1/2*[1/3-2/4+1/5]
..............................................................................
1/(26*27*28)=1/2*[1/26*27-1/27*28]=1/2*[(1/26-1/27)-(1/27-1/28)]=1/2*[1/26-2/27+1/28]
1/(1*2*3)+1/(2*3*4)+1/(3*4*5)+.....+1/(26*27*28)
=1/2*{[1/1-2/2+1/3]+*[1/2-2/3+1/4]+[1/3-2/4+1/5]+...+[1/26-2/27+1/28]}
=1/2*{1-1/2-1/27+1/28}
=1/2*377/756
=377/1512
初一绝对值计算题：∣1/2-1/3∣+∣1/3-1/4∣+∣1/4-1/5∣+.+∣1/2010-1/2011
∵1/2>1/3
∴去掉绝对值符号之后∣1/2-1/3∣=1/2-1/3
全拆开之后发现是1/2-1/3+1/3-1/4+1/4-1/5+......+1/2010-1/2011
符合格式a-b+b-c+c-d+d……-n+n-m
所以去掉中间-x+x格式的东西 就剩下a-m
也就是 1/2-1/2011
通分 计算 得出1/4022
初一数学计算1/(1+2)+1/(2+3)+1/(3+4)+.1/(99+100)请帮助解答
|1/2|+|1/3-1/2|+……+|1/99-1/98|+|1/100-1/99|=？运算规律
|1/2|+|1/3-1/2|+……+|1/99-1/98|+|1/100-1/99|
=1/2+(1/2-1/3)+...+(1/98-1/99)+(1/99-1/100)
=1/2+1/2-1/100
=1-1/100
=99/100
1/3:1/4:1/5（：等于比）初一数学题，化简比
1/3:1/4:1/5
=1/3×60:1/4×60:1/5×60
=20:15:12
:|1/2-1|+|1/3-1/2|+|1/4-1/3|+.+|1/2008-1/2007|+|1/2009-1/2008|解题方法
:|1/2-1|+|1/3-1/2|+|1/4-1/3|+...+|1/2008-1/2007|+|1/2009-1/2008|
=（1-1/2）+（1/2-1/3）+（1/3-1/4）+---+（1/2008-1/2009）
=1-1/2009
=2008/2009
求和：|½-1|+|1/3-1/2|+……+|1/99-1/98|+|1/100-1/99|
因为|1/n-1/(n-1)| = 1/(n-1) - 1/n
所以原式 = 1 - 1/2 + 1/2 - 1/3 + 1/3 - …… -1/100
= 1 - 1/100
= 99/100
初一数学练习题1×1/2=1-1/2;1/2×1/3=1/2-1/3;1/3×1/4=1/3-1/4;. 写出这一组式子所表达的一般规律
1/n×1/(n+1)= 1/n - 1/(n+1)
