How many sides does a circle have?

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?

Before Mount Everest was discovered, what was the highest mountain in the world?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

What has one letter and starts with an E?

How can you write nineteen in a manner that if we take out one, it becomes twenty?