1. Brain Teaser 1 What is the significance of the following:
The year is 1978,
thirty-four minutes past noon
on May 6th.
The time and month/date/year
American style calendar are 12:34, 5/6/78.

2. How much dirt would be in a hole None. No matter how big a hole is,
Brain Teaser 2
How much dirt would be in a hole
6 feet deep and 6 feet wide that
has been dug with a square edged shovel?
None. No matter how big a hole is,
it's still a hole: the absence of dirt.

3. Brain Teaser 3 What can go up a chimney down,
but can't go down a chimney up?
An umbrella.

4. What is it that goes up and goes down
Brain Teaser 4
What is it that goes up and goes down
but does not move?
The temperature

5. Brain Teaser 5
I dig out tiny caves, and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help, yet many people are afraid to let me help them. 
Who am I?
A Dentist.

6. Brain Teaser 6
When asked how old she was, Mary replied, "In two years I will  be twice as old as I was five years ago." How old is she?  12

7. Brain Teaser 7
An elderly man is going for a walk.  Two young men in excellent  physical condition are directly behind him, sprinting toward  him.  No matter how fast they run, they do not catch up with the man. 
Why can't the men catch up with the elderly man and where  are all three people?
The three people are on treadmills in a gym. 

8. What are the people taking and which type of business employs Mike.
Brain Teaser 8
A steady stream of people enter Mike's place of business and remove its treasured belongings.  The people do not pay for what  they take.  Mike allows them to take as much as they can carry  as long as they keep their mouths shut. 
What are the people  taking and which type of business employs Mike.
The people are taking books
and Mike works for a Library.

9. Let enough air out of the tires to lower the truck.
Brain Teaser 9
There is a low railroad bridge in your town.  One day you see a  large truck stopped just before the underpass.  When you ask  what has happened, the driver tells you that his truck is one inch higher than the indicated height of the opening.  This is the only road to his destination. 
What can he do to get through  the underpass the easiest way?
Let enough air out of the tires to lower the truck. 

10. Plant one tree at each point and one tree where the sides intersect.
Brain Teaser 10
Little Johnny buys 10 trees at a local nursery. How does he  plant these 10 trees in 5 rows with 4 in each row? 
Draw a 5 pointed star.
Plant one tree at each point
and one tree where the sides intersect. 

11. Brain Teaser 11
I have four letters. The first two stand for a boy. The first three stand for a girl. All of my letters stand for brave boy.
What word am I?
Hero

12. Everyone on the bus was married
Brain Teaser 12
My brother, the local bus driver, was telling me that recently  he was driving a bus full of people and no-one got off on the  way. However, at the end of the journey, there was not a single  person left on the bus. How?
Everyone on the bus was married
and therefore not single.

13. Brain Teaser 13 We were four, one was cut and we were five.
What are we? 
The answer is the Roman numeral IV.
It stands for 4, and if the  one (I)
is taken out, it becomes Roman numeral V,
which is five.

14. Jeff had 17 rings and all but 9
Brain Teaser 14
Jeff had 17 rings and all but 9
were dropped down the drain,  how many did he have left? 
Nine.

15. Brain Teaser 15
Correct the following equation so that it makes sense by freely  moving the given four digits but without introducing any  additional mathematical symbols.
79 = 24
72 = 49

16. Brain Teaser 16 www.mathsrevision.com
How quickly can you find out what is unusual about this  paragraph? It looks so ordinary that you would think hat  nothing was wrong with it at all and, in fact, nothing is. But  it is unusual. Why? If you study it and think about it you may  find out, but I am not going to assist you in any way. You must  do it without coaching. No doubt, if you work at it for long, it  will dawn on you. Who knows? Go to work and try your skill. Par  is about half an hour. 
The paragraph does not contain any instances of the letter 'e', the  most common letter in the English alphabet. 

17. A clerk in the butcher shop is
Brain Teaser 17
A clerk in the butcher shop is
5 feet 10 inches tall.
What does  he weigh?
Meat.

18. If there are three apples
Brain Teaser 18
If there are three apples
and you take away two,
how many do you have?
Two.

19. If you have only one match
Brain Teaser 19
If you have only one match
and you walked into a room where  there was an oil burner, a kerosene lamp
and a wood burning  stove.
Which one would you light first? 
The Match 

20. Two men play five games of checkers.
Brain Teaser 20
Two men play five games of checkers.
Each man wins the same  number of games.
There are no ties. Explain this. 
The two men weren't playing each other. 
The two men weren't playing each other.