23+29+227+281+2243．

Question

(2)/(3)+(2)/(9)+(2)/(27)+(2)/(81)+(2)/(243)．

Answer 1

(2)/(3)+(2)/(9)+(2)/(27)+(2)/(81)+(2)/(243)
=1-(1)/(3)+(1)/(3)-(1)/(9)+(1)/(9)-(1)/(27)+(1)/(27)-(1)/(81)+(1)/(81)-(1)/(243)
=1-(1)/(243)
=(242)/(243)