Make hundred!

Try simple but highly intellectual game of mind - though you don't need any special tools, even piece of paper actually, it will bring you a few minutes of real enjoyment! If you're using public transport, this is a perfect way to kill time if you don't wanna read book or newspaper. If you drive a car, that's the excellent way to cool down yourself when you're stuck in a jam and getting an hour late to important business meeting. Just take any four digits from 0 to 9 (for example, from the number of brilliant limousine in front of you or of the metro carriage in which you suddenly stopped in the middle of tunnel) and using usual arythmetic operations try make 100 out of them. Start with very simple ones like

1010: 10*10=100 or

5555: (5+5)*(5+5)=100

to feel yourself very clever: "Hey! I did it!", then gradually increase the difficulty of problem - for example, try invent another, more pertinent way of solving very simple problem. Say, start using factorials (you don't know what this factorial is??? Oh, it's easy: 1!=1, 2!=2, n!=(n-1)!*n - got it? Are you sure?!?!? Then tell me what is 5!? Right, 120. How did you know?) Now you get another elegant way to make 100 out of 5555. Ready? Not??? Come on, that's easy!

5!+5-5*5=100

How about it??? More operations, instead without braces. So, are you in? If you didn't feel the beauty of the game yet, maybe that's because I made it for you? Ok, it's time to try your own brains!!! For the beginning, a couple of simple but very beautiful examples. Try to get 100 out of:

4444
7275
7572

using +, -, *, /, !, (), ^ (power), and sqrt (square root). USE ALL DIGITS! Some bonton rules: avoid if possible multiplication/division by 1 and don't use periodic fractions like 33.(3). When ready, try more difficult (and hense more beautiful) ones:

3333
7919 (it's a joke:)
7918 (it's not a joke!)
7917 (and this one too!)
7916 (in case you didn't manage with previous two:)

If you've made them all - you're a genious, if not - I am the one! ;-)

Report your results to me - if you like it, I'll give you more! If you have other combinations to solve, send them to me - let's see who makes them faster!!!


Denis Denissenko (denis@hea.iki.rssi.ru)

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