1/1*2+1/2*3+1/3*4+1/4*5+·········+1/2006*2007+1/2007*2008=?(
(1+3+5······+2007+2009+2011)-(2+4+6+·····+2006+2008+2010)
计算1+2-3-4+5+6-7-8+······+2005+2006-2007-2008+2009
1-2+3-4+······+2007-2008=?(用简便方法运算)
1+2++3+··········+10000=
计算: 1-2=3-4+5-6+···+2007-2008-2009=
计算:1+(-2)+3+(-4)+···+2005+(-2006)+2007+(-2008).
计算(1-1/2)* (1-1/3)*(1-1/4)*······(1-1/2006)*(1-1/2007)
俗语和名句的填空1······,自知之明.2······,行必果.3工欲善其事,······.4临渊羡鱼,······.
1+2+3+4+5+6······38+39=?
计算1-2+3-4+5-6+······-98+99=
1+2+3+4+5······+100+101=几
计算 1*2/1+2*3/1+3*4/1+············+2009*2010/1