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Reducing Fractions

When you add or multiply fractions, you will very often end up with a big fraction that is hard to work
with. You can almost always reduce such a fraction into one that is easier to handle.


Start   Small
It is not easy to see that
26 and 286 have a com-
mon factor of 13, but it’s
pretty clear that they’re
both divisible by 2.
So start from there.

To reduce a fraction, divide both the top and the bottom by the largest number that is a factor of both. For


example, to reduce , divide both the top and the bottom by 12, which is the largest number that is a


factor of both. Dividing 12 by 12 yields 1; dividing 60 by 12 yields 5. The reduced fraction is .


If you can’t immediately find the largest number that is a factor of both, find any number that is a factor of


both and divide both the top and bottom by that number. Your calculations will take a little longer, but


you’ll end up in the same place. In the previous example, even if you don’t see that 12 is a factor of both

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