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

How can you take 2 from 5 and leave 4?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

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

Explain?

I know a nine-letter word having only one vowel.
Do you ?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

What jumps when it walks and sits when it stands?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

There is a five-letter word which has 3 consonants(all are same) and 2 different vowels.
Also, something wrong is associated with the word.

Can you name it?