When
we have both additions and subtractions, we follow the same process as when we have additions
only:
In order to
add or subtract fractions, they must have the same denominator.
If the fractions
have different denominators, you have to find a common denominator,
that is, they are changed by other equivalent fractions but all
with the same denominator.


In order
to do this, follow the following steps:
 First find
the least common multiple of the denominators and make it the denominator
of each fraction.
 Next, in
order to find each of the new numerators, divide that number by the denominator
of a fraction and multiply it by the numerator.
Finally,
add and subtract the numerators and enter the same denominator.
 Simplify
if possible.
In
this window you can see the process step by step by clicking on
the blue triangle.
When
you click on Init other fractions will appear. Try to do it several
times.

