[2011/3]+[2011/9]+[2011/27]+[2011/81]+[2011/243]+[2011/729]+[2011/2187]
=2011×(1/3+1/9+1/27+1/81+1/243+1/729+1/2187)
=2011×(1-1/2187)÷(3-1)
=2011×2186/2187÷2
=2011×1093/2187
=2198023/2178
≈1009.2
[2011/3]+[2011/9]+[2011/27]+[2011/81]+[2011/243]+[2011/729]+[2011/2187]
=2011×(1/3+1/9+1/27+1/81+1/243+1/729+1/2187)
=2011×(1-1/2187)÷(3-1)
=2011×2186/2187÷2
=2011×1093/2187
=2198023/2178
≈1009.2