The product of two outer terms of a ratio is 2, one inner term is 5, and what is the other inner term.
一个比例的两外项之积是2，一个内项是5，另一个内项是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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