Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

What does this mathematical rebus means ?

What is next number in the pattern below:

131 517 192 123 ?

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

What has one eye, but can’t see?

When 99 is considered higher than 100?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

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

What question can you never answer yes to?