If eleven plus two equals one, what does nine plus five equal?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

I have no life, but I can die. What am I?

Can you write down eight eights so that they add up to one thousand?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

A person was found dead on a big green land with no trees or buildings around. When the police arrived, they found a piece of rock lying next to him and the man was wearing clothes comprising of red, blue and yellow colours.

Can you tell who the person is and what was the cause of death?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

Before Mount Everest was discovered, what was the highest mountain in the world?