1/1×2+1/2×3+1/3×4+···+1/2004×2005=
1、2、3···2004、2005、2006按
(1+1/2)(1-1/3)(1+1/4)(1-1/5)··········(1-1/2005)(1+1/2006)=_
数学计算.(1乘2+2乘3+3乘4+4乘5+·····+2004乘2005=?)
1+2++3+··········+10000=
有理数加减运算(-1)+(+2)+(-3)+(+4)+·····(-2001)+(2002)+(2003)+(2004)
(1-2)×(2-3)×(3-4)×······×(19-20)=
1\(2\3)\(3\4)······\(18\19)\(19\20)=
计算 1*2/1+2*3/1+3*4/1+············+2009*2010/1
1/2004+2/2004+3/2004······+100/2004简便算,算式思路!
数学计算题1-2-3+4+5-6-7+8+···+2001-2002-2003+2004+2005-2006
1+2+3+4+5+6······38+39=?
1+2+3+4··· ···+78+79=?