By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Why do people go to bed?

John went to a parrot shop in Mexico, and the parrot owner told him that his parrot is so unique that he repeats everything he hears. John got excited and immediately bought the parrot. John went home and spoke many words, but the parrot does not repeat anything.
He went again to the parrot shop and complaint to the shopkeeper, but the shopkeeper never lied. Explain?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

I am lying and I always lie. Tell me whether I am lying or telling the truth.

What does this rebus mean?

O
N
C
E
TIME

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

Can you identify if it's a murder or a suicide ?