1/2-1/3=1/6 1/3-1/4=1/12 .根据算式简算下面算式的和 1/6+1/12+1/20+1/30+1/42+1/56 等于?

1+2+3/6+1/4= 巧算：(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)*(1/2+1/3+1/4+1/5)(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)*(1/2+1/3+1/4+1/5)===== 1-1/2+1/3-1/4+1/5-1/6+1/7.-1/50=? 1/1*3+1/2*4+1/3*5+1/4*6+.+1/100*102=? 1-1/2+1/3-1/4+1/5-1/6+…+1/15=23*[1/( )+1/( )+1/( )+1/( )] 1/2+1/3+1/4+1/5+1/6+1/7+.1/20= 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 1/2{1/3[1/4(1/5x-1)-6+3}=1 解方程 1/2{1/3[1/4(5/1x-1)-6]+3}=1 (-3/4)+(-1/6)-(-1右-1/2)=多少? 1/4-1/5=1/18+1/6=1/2-1/8=7/11+5=1/3+1/4=2-1/3= 1/2{1/3[1/4(1/5x-1)-6]+4}=1 1.（1+1/2+1/3+1/4）*（1/2+1/3+1/4+1/5）-（1+1/2+1/3+1/4+1/5）*（1/2+1/3+1/4）=2.（1+1/2+1/3+1/4+1/5）*（1/2+1/3+1/4+1/5+1/6）-（1+1/2+1/3+1/4+1/5+1/6）*（1/2+1/3+1/4+1/5）= 2×3/1+3×4/1+4×5/1+5×6/1+.199×200/1=? 1/2+1/3+1/4=? 1/2-3/1-4/1= 因为1-2/1=2/1,2/1-3/1=6/1,3/1-4/1=12/1,所以2/1+6/1=1-2/1+2/1-3/1=1-3/1=3/2 2/1+6/1+12/1=1-2/1+2/1-3/1+3/1-4/1=1-4/1=4/3