So first off you need to work out how many days there were in the war.
there are 365 days in a year, and 1916 was a leap year so it had 366 days.
You do 365 + 365 + 366 + 365 to work out how many days until august 4th 1918.
365 + 365 + 366 + 365 = 1461
now you need to calculate the days from august 4th until november 11th
you do (31 - 4) + 30 +31 + 11 = 99 days
total days = 99 + 1461 = 1560
to find out how many died per day you do 10000000/1560 = 6410
