Death: 1899 03 18 --> 1899 02 --> 1898 13 
Birth: 1805 04 27 --> 1805 04 --> 1805 03 
Alive from April 27th to 30st  in 1805 = 4 days
Alive from March 1st to 18th, but don't count last day = 17 days
Total of 21 days.

Giving an age of 93 years 10 months 21 days