It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

Can you write down eight eights so that they add up to one thousand?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

I am an odd number. Take away a letter and I become even. What number am I?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

How many times can you subtract the number two from the number fifty?

The husband and wife were jogging in the morning. To match every two steps of the husband, the wife required three steps. If Both of them start with the here right foot. After how many steps do their left foot be together?

Can you find the 09 errors in the picture below?