Puzzle 73 - Product

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 Do you know the sum of 1+2+3+....+1000=? How fast can you find out the sum? 

OK, let us go in steps. How much is 1+2+3+..+10? Is it 55? Did you add all the numbers? Really? Did you add all the numbers? 

Then certainly you can't find out sum of all the numbers from 1 to 1000. You will be bored to death before you finish adding them. The formula my dear is 1+2+...+n = n(n+1)/2

You already knew it? You are the smart one! Aren't you?

OK. Now for the real puzzle of today.

What is product you get when you multiply all the numbers on your telephone? 

(You must have seen a telephone, a landline telephone? Even if you haven't, what is the product of numbers on your mobile, when you try to dial some number - product of all numbers on the the numeric keypad. Excluding backspace and hash. We are not into cryptography - yet!)

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