A simple mathematical logic says -
odd + odd = even
odd + even = odd
even + odd = odd
even + even = even
Now since you know this have a look at the small riddle below -
A friend of mine runs a small poultry farm in Bangalore. She took me round to see the place. I counted the number of chickens. There were 27 of them. And there were 4 enclosures. I noticed that in each enclosure there were an odd number of chickens.
Can you tell how many there were in each enclosure?