Simplest form

You know that: \frac{4}{12} = \frac{2}{6} = \frac{1}{3}

{4} and {12} have a common factor, namely {4}, so \frac{4}{12} can be written as \frac{1}{3} (divide the top and the bottom by 4).

{2} and {6} have a common factor, namely {2}, so \frac{2}{6} can be written as \frac{1}{3} (divide the top and the bottom by {2}).

However, {1} and {3} have no common factors, so \frac{1}{3} cannot be simplified. When a fraction cannot be simplified we say that it is its simplest form.