1/9+1/99+1/999+1/9999
=1111/9999+101/9999+1/999+1/9999
=1213/9999+1/999
=134643/1109889+1111/1109889
=135754/1109889
约=0.1223
1/9+1/99+1/999+1/9999
=1111/9999+101/9999+1/999+1/9999
=1213/9999+1/999
=134643/1109889+1111/1109889
=135754/1109889
约=0.1223