LeapQ[Y_] := 
      Or[
And[IntegerQ[(Y/4)], 
          Not[IntegerQ[(Y/100)]]], 
IntegerQ[
          (Y/400)]]

LeapQ[2012]

LeapQ1[Y_] := 
And[IntegerQ[(Y/4)], 
        Or[Not[IntegerQ[(Y/100)]], 
IntegerQ[
            (Y/400)]]]

LeapQ1[2012]

LeapQ1[2000]

LeapQ1[2100]

LeapQ1[2011]