Question

(1+3+5+7.+2005)-(2+4+6+8.+2004)怎么算

Answer 1

(1+3+5+7.+2005)-(2+4+6+8.+2004) =(1-2)+(3-4)+.+(2003-2004)+2005 =(-1)*(2004/2-1+1)+2005 =(-1)*1002+2005 =-1002+2005 =1003