[Since -12.2 and -11.8 are non-integers, the intersection is the empty set { } if ( -12.2, -11.8 ) means the set of the two numbers.] If the question means the range -12.2 to -11.8 (the set of all numbers in the range, excluding -12.2 and -11.8 themselves), then there is but one integer, -12, within this range and the intersection is { -12 } or simply -12. The question in words would be: What integer(s) lie(s) between -12.2 and -11.8? The answer is -12.