In a ratio, two inner terms are reciprocals of each other, one of which is 3, and the other is how much.
在一个比例里，两个内项互为倒数，其中一个外项是3，另一个外项是多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>