In English "eighteen fifty" is standard.
If you are writing out the whole number (with thousand), American English does not require an "and": "one thousand eight hundred fifty."
In British English it would be eighteen hundred and fifty or eighteen fifty. A previous one was actually accepted in the former format.
'El ano 1850' was rejected. Why do they accept numbers for some questions and not others? I didn't even have the option to suggest that this should be accepted.
In the year 2525, if man is still alive............ you may find..............