When communicating in Chinese you may often make mistakes using Chinese grammar like:

False:

    这是二分之三。

    Zhèshì èr fēn zhī sān.

True:

    这是三分之二。

    Zhèshì sān fēn zhī èr.

二分之三（two—thirds）是受英语分数表示方法的影响。英语要以分子为基数词，分母为序数词，并有复数。汉语的表示方法是先说分母，后说分子，应该为三分之二。

二分之三（two-thirds）is derived from the English way of showing fractions. In English, the numerator is a cardinal number whereas the denominatior is an ordinal number which may appear in the plural form. In Chinese, the denominatior always comes before the numerator. Thus it should be 三分之二.