Dumb percentage question?

Why do we multiply by 100 while calculating percentage ?

    example : 2/100 * 100 =2%

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It is because 2% is easier to visualize as compared to 0.02. For example, if I am talking about a small gain of money, 0.1% is a lot easier to 'visualize' as compared to 0.001. –  picakhu Jul 11 '12 at 12:32
% is a notation symbol that means "divided by 100". –  Djaian Jul 11 '12 at 13:05

% represents out of $100$. If you have $a$ things out of $n$,then what would you have if there were $100$ things in total, that is given by percent.

Now, Suppose you have $a$ things out of total of $b$ things ,then,

$\implies$ if there were total number of things =$1,$ then you would have = $\frac{a}{b}$ things out of $1$ thing

$\implies$ if total number of things$=100\implies$ you would have $=\frac{a}{b}\times 100$ out of those $100$ things and this is what calculating percent is.

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first 2 lines are clear to me but the example is still not clear. –  user286035 Jul 11 '12 at 14:07