1-(2/3)-(2/9)-(2/27)-(2/81)-(2/243)-(2/729)=1-2*[(1/3)+(1/3^2)+(1/3^3)+(1/3^4)+(1/3^5)+(1/3^6)]=1-2*[(1/3)-(1/3^6)×(1/3))]/[1-(1/3)]=1-2*[(3^6)-1]/(2*3^6)=1-[(3^6)-1]/(3^6)=1-(3^6)/(3^6)+1/(3^6)=1/729
三十五除以八分之七乘一减七分之二