Can you find the missing piece of the Porsche?

Can you tell a 3D object that has just two surfaces?

I have feet, but no legs. Which animal Am I?

What jumps when it walks and sits when it stands?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

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?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

When can we add 2 to 11 and get 1 as the correct answer?