You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Can you fill the blank with the correct number?

6 30 870 756030 _____

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

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

What is the difference between a jeweller and a jailer?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Find the missing number in the image below.

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

It has five wheels, though often think four, You cannot use it without that one more, You can put things in it, you can strap things on top, You can't find it in the market, but you can still go shop. What is it?

There is something which you can be arrested for attempting but not for successfully completing.