How can you make number one disappear by adding something to it?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

What occurs twice in a week, once in a year but never in a day?

How could a baby fall out of a twenty-story building onto the ground and live?

How many bananas can you eat if your stomach is empty?

Usually, a boxing match consists of twelve rounds. In a particular friendly match between two heavyweights, the match was finished in the ninth round itself as one of the boxers knocked out the other one.

But, in that fight, no man threw even a single punch.

How can this be possible?

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

Manish and Manoj play 5 games of chess.
Both Manish and Manoj win the exact same number of games. There is no tie at all.

How?