I chose to write the number in words for the practice - however the 's' on the end of " cents " was 'red-marked' as incorrect.
Under both the traditional and reformed "spellings", I think there should be a terminal 's' following cents in 'deux cents', and unless there is something different about the use with weights (and measures?), the example in the attached lesson (using reformed spelling) seems to confirm this - ' deux-cents soldats '.
This applies to all the whole number multiples of 100 from 200-900.
Expressing large numbers -thousands/millions/billions - in French