# Adding and subsctracting fractions with more than two parts

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• July 16th 2012, 04:10 AM
ariel32
Adding and subsctracting fractions with more than two parts
i need to do 0.333 + 0.25 + 0.083 in fractions now i know how to do two parts by finding the common factor and multiplying but how do i do three parts?
• July 16th 2012, 04:30 AM
Plato
Re: Adding and subsctracting fractions with more than two parts
Quote:

Originally Posted by ariel32
i need to do 0.333 + 0.25 + 0.083 in fractions now i know how to do two parts by finding the common factor and multiplying but how do i do three parts?

You don't need to do that.
$\frac{333}{1000}+\frac{250}{1000}+\frac{83}{1000}= ~?$
• July 16th 2012, 04:36 AM
emakarov
Re: Adding and subsctracting fractions with more than two parts
Also, the sum of more than two numbers can always be represented as a repeated sum of just two numbers at a time. Thus, 0.333 + 0.25 + 0.083 is either (0.333 + 0.25) + 0.083 or 0.333 + (0.25 + 0.083) (these two expressions give the same result).
• July 16th 2012, 11:45 AM
HallsofIvy
Re: Adding and subsctracting fractions with more than two parts
I suspect that the problem was really $\frac{1}{3}+ \frac{1}{4}+ \frac{1}{12}$
Since 12= 3(4), the "least common denominator" is 12. Multiplying both numerator and denominator of the first fraction by 4 and of the second fraction by 3 gives
$\frac{4}{12}+ \frac{3}{12}+ \frac{1}{12}$.

However, ariel32, the question you asked is not at all that problem. While ".333" and ".083" are approximations to $\frac{1}{3}$ and $\frac{1}{12}$, they are not equal to them. In the future, please state your problem exactly as you were given it.