There is a ratio whose two outer terms are both 0.5, then what is the reciprocal of the product of its two inner terms.
有一个比例，它的两个外项都是0.5，那么它的两个内项乘积的倒数是多少．
<gadget id="calculator">0.5 * 0.5</gadget>
<output>0.25</output>

<gadget id="calculator">1 / 0.25</gadget>
<output>4</output>

<result>4</result>