In order to reduce  , the numerator and denominator must share a common factor. This common number must evenly divide into both of them without any remainder or decimal.
In order to completely reduce the fraction, you must divide the numerator and the denominator by the greatest common factor (GCF). The GCF of  and  is  (note: click here if you need help with finding the GCF). So divide both the numerator and denominator by
In other words, to reduce the fraction you do this
 Plug in the numerator, denominator, and the GCF
 Now divide 42 by to get 42. This is now the new numerator.
Now divide 55 by to get 55. This is now the new denominator.
So
This means that reduces to
In other words, 
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