How many times can you subtract the number 5 from 25?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

The following question it puts forth you:

25 - 55 + (85 + 65) = ?

Then, you are told that even though you might think it's wrong, the correct answer is actually 5!

Whats your reaction to it? How can this be true?

Can you find the missing piece of the Porsche?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

A man was driving a black truck. His lights were not on. The moon was not out. A lady was crossing the street. How did the man see her?

A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.

How will they cross the river?

In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?

Why is Saturday stronger than Monday?

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?