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     How do you convert fractions to decimals?  Well, its simple.  You divide the numerator by the denominator.  Then, if you have to, you add a zero at the end in order to complete the decimal.  If the decimal goes on further than the thousandths place, then you stop and round to the hundredths place.
     Now for changing decimals to fractions, that is different.  There are different ways to change them, but what I usually do, for example, to simplify .05, I would change it into 5/100.  Then, I would simplify it.  If you divide it by 5 then you get 1/20.  That is the simplest form, so that would be the fraction.  All in all, they are very similar, but also have multiple steps in order to solve them.

 
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     Say you were in a restaurant, would you pay for the food in ratio or percentage?  I would pay for it in percentage.  What would you do?  Now, you're probably wondering why I am asking these weird questions, but it's a math situation.  Here is why I would pay in percentage.
     I would use percentage because you use percentage already to pay for food.  You might not realize it, but you do.  Tax is a percentage of your bill.  So are tips!  Usually you tax is 8-9% of your bill.  Plus, you use percentages to find out the tip.  The tips vary from 10-15% usually, however some people only tip say 8%.