The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

There is a box. The area of its top is 240 square units, the area of the front is 300 square units and the area of the end is 180 square units.

Can you calculate the dimensions of this box with the given data?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

Prove that twice of ten is the same as twice of eleven.

What is the riddle which can be asked all day with a different correct answer each time.

John and his team plan to rob a safe. They got just one chance to break the code else the local police will be informed. Below are clues:
A) Exactly one number is perfectly placed: 9 8 1
B) Everything is incorrect: 9 2 4
C) Two numbers are part of the code of the safe but are wrongly placed: 0 9 3
D) One number is part of the code of the safe but is wrongly placed: 1 4 7
E) One number is part of the code of the safe but is wrongly placed: 7 8 3

You need to move three matchsticks to form three squares. Can you do it?

Can you count the number of triangles in the given picture?