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?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

Can you solve this picture maths equation?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

Can you find the missing piece of the Porsche?

If you say my name, I will no longer exist. What am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?