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

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

If an electric train is travelling south, then which way is the smoke going?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

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?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

A man started to town with a fox, a goose, and a sack of corn. He came to a stream which he had to cross in a tiny boat. He could only take one across at a time. He could not leave the fox alone with the goose or the goose alone with the corn. How did he get them all safely over the stream?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

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?