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

81 x 9 = 801. What must you do to make the this equation true?

When is the top of a mountain similar to a savings account?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?

You can win me and lose me but never buy me
You can not eat me and never want to part with me
I can make you cry or bring you joy
I am not a machine and definitely not a toy
You keep me but i am not forever just yours
You might find me in a case or on a shelf next to a vase
I am hard and i am tall if you bump me i am sure to fall
I am made of different materials and am at many events
If your lucky and fight hard I might be yours
What am I ?

How many times do a clock's hands overlap in a day ?

The more of this there is, the less you see. What is it?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?