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?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

What has a ring but no finger?

Why do we preferably have round manhole covers and not square ones?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

I am soft and cuddly that soothe your heart. But, If you pick my last name I am going to tear you all apart. Who am I?