1-1/2+1/3-1/4+1/5-1/6+1/7.-1/50=?
1-1/2-1/3-1/4-1/5-1/6-1/7.-1/99=多少?
2*1+4*3+6*5+8*7.+50*49
1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+.1/(1+2+3+4+5+6+.+50)=?
1+2+3+4+5+6+7...+999+1000=?
1+2-3+4-5+6-7.+2013-2014=?
1+2+3+4+5+6+7.+1000=多少?
-1/2,+1/3,-1/4,+1/5,-1/6,.
(1-1/2)*(1-1/3)*(1-1/4)*(1-1/5)*(1-1/6)*…*(1-1/19)*(1-1/20)=
1/2{1/3[1/4(1/5x-1)-6]+4}=1
6/1{4/1[3/1(2/1x-1)+3]+5}=1 解方程
1/6【1/4{1/3(1/2X-1)+3}+5】=1
简算 (1-1/2+1/3-1/4+1/5-1/6+...+1/49-1/50)/(1/26+1/27+...+1/50