A fraction is reduced once by 2, once by 3, and once by 5 to obtain the simplest fraction (2/5). What is the original fraction?
一个分数用2约一次，用3约一次，用5约一次得到最简分数(2/5)，这个分数原来是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>