Our product and our sum always give the same answer. Who are we?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.

What always comes into a house through the keyhole?

I have an eye but still cannot see.

Who am I?

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

Forwards I am heavy, backward I am not. What am I?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

Replace the letters of words with a number so that the below equation holds true

BASE +
BALL
---------
GAMES
----------

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

Identify the 10 differences between the two given pictures.