In a Query?
EvenNumbers:[FieldName] Mod 2 = 0
The result will be -1 (True) if the value is an even number
The result will be 0 (False) if the value is an odd number
or...
OddNumbers:[FieldName] Mod 2 = 1
The result will be -1 (True) if the value is an odd number
Thwe result will be 0 (False) if the value is an even number