The simplest form of a fraction is $\,\displaystyle\frac{N}{D}\,$,
where $\,N\,$ and $\,D\,$ have no common factors (except $\,1\,$).
Thus, in simplest form, there is no number other than
$\,1\,$ that goes into both
the numerator and denominator evenly.
EXAMPLES:
Question:
Write in simplest form:
$\displaystyle\frac{6}{15}$
Solution:
The fraction
$\,\frac{6}{15}\,$ is not in simplest form,
because $\,6\,$ and $\,15\,$
have a common factor of $\,\bf{3}\,$.
To simplify the fraction, use the following thought process:

$6\,\,\,$ divided by $\,\bf{3}\,$ is $\,2\,$
(the new numerator is $\,2\,$)

$15\,$ divided by $\,\bf{3}\,$ is $\,5\,$
(the new denominator is $\,5\,$)

Thus,
$\,\cssId{s20}{\frac{6}{15}}
\cssId{s21}{= \frac{6\div\bf{3}}{15\div\bf{3}}}
\cssId{s22}{= \frac{2}{5}}\,$.

Since
$\,2\,$ and $\,5\,$ have no common factor other than $1$,
the simplest form of
$\,\frac{6}{15}\,$ is
$\,\frac{2}{5}\,$.
Note:
$\displaystyle
\cssId{s26}{\frac{6}{15}} \ \
\cssId{s27}{= \ \ \frac{3\cdot 2}{3\cdot 5}}
\cssId{s28}{\ \ = \ \ \frac{3}{3}\cdot\frac{2}{5}} \ \
\cssId{s29}{= \ \ 1\cdot\frac{2}{5}} \ \
\cssId{s30}{= \ \ \frac{2}{5}}\,$
Thus, simplifying a fraction is just getting rid of extra factor(s) of $\,1\,$.
Question:
Write in simplest form: $\frac{2}{6}$
Answer:
$\frac{1}{3}$
In the exercises below, you will input fractions using a forward diagonal slash.
For example,
$\,\frac{1}{3}\,$
is input as 1/3 .