What always comes into a house through the keyhole?

Three playing cards in a row. Can you name them with these clues? There is a two to the right of a king. A diamond will be found to the left of a spade. An ace is to the left of a heart. A heart is to the left of a spade. Now, identify all three cards.

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

What does this Rebus Picture means ?

Imagine you are in a room with no windows or doors. How will you get out?

Using eight eights and addition only, can you make 1000?

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

A man had five children. He had $100 with him to give to his children. He decided to start with the youngest child and then give $2 more than each younger child to his next elder child.

For example, if he gives $x to the youngest child, he will give $(x+2) to the next one, $[(x+2) + 2] to the next one and so on.

Can you find out how much did the youngest one receive?

A man is walking down a road with a basket of eggs. As he
is walking he meets someone who buys one-half of his eggs
plus one-half of an egg.
He walks a little further and meets another person who buys
one-half of his eggs plus one-half of an egg.
After proceeding further he meets another person who buys
one-half of his eggs plus one half an egg. At this point, he
has sold all of his eggs, and he never broke an egg.
How many eggs did the man have to start with?

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