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

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

I have an eye but still cannot see.

Who am I?

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
=====
* * *

One night, a man runs away from home. He turns left and keeps running. After some time he turns left again and keeps running. Later, he turns left one more time and runs back home—but when he gets home, he finds a man in a mask. Who was the man in the mask?

A father is locked up in jail. His wife has gone bankrupt. Their male child has to sell his hotel in order to gain some money. Yet their girl child does not care and is quite happy.

How can someone be so rude?

Bea Smith, Vera Bennett, Franky Doyle and Doreen Anderson were in Wentworth Prison for murder. But their behaviour in the jails is appreciated by the warden and the warden decided to give all these 4 prisoners 11 cupcakes. They all like cupcakes and they had all cupcakes in no matter of time but they do not know how many cupcakes each individual had. Therefore Bea started the conversation Bea: "Hey T-Vera, did you have more cupcakes than I had ?"Vera: "I do not know girl, Hey Franky, did you have more cupcakes than I had ?".Franky: "I do not know"Doreen replied instantly: "I know how exactly how many cupcakes each of you had?" So can you tell how many cupcakes each of them had?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

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