Can you fill the blank with the correct number?

6 30 870 756030 _____

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.

I can be cracked, made, told, and played. What am I?

What is at the end of a rainbow?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

It belongs to you, but other people use it more than you do. What is it?

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

A game is being played where eight players can last for thirty-five minutes. Six substitutes alternate with each player in this game. Thus, all players are on the pitch for the same amount of time including the substitutes.

For how long is each player on the pitch?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?