$${\frac{{\mathtt{2\,707}}}{{\mathtt{999}}}}$$ Normally we would try to reduce this down to it's simplest form by finding a number (their greatest common divisor) that could divide both the top number (numerator) and bottom number (denominator) to give us whole numbers for the numerator and denominator, this would be called a proper fraction.
e.g. $${\frac{{\mathtt{2}}}{{\mathtt{4}}}}$$ divided by 2 is simplified to $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}$$
$${\frac{{\mathtt{2\,702}}}{{\mathtt{999}}}}$$ does not have a greatest common divisor to reduce or simplify it whilst keeping it as proper fraction. Therefore, it is called an irreducible fraction and remains as it is.
$${\frac{{\mathtt{2\,707}}}{{\mathtt{999}}}}$$ Normally we would try to reduce this down to it's simplest form by finding a number (their greatest common divisor) that could divide both the top number (numerator) and bottom number (denominator) to give us whole numbers for the numerator and denominator, this would be called a proper fraction.
e.g. $${\frac{{\mathtt{2}}}{{\mathtt{4}}}}$$ divided by 2 is simplified to $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}$$
$${\frac{{\mathtt{2\,702}}}{{\mathtt{999}}}}$$ does not have a greatest common divisor to reduce or simplify it whilst keeping it as proper fraction. Therefore, it is called an irreducible fraction and remains as it is.