In a ratio, the product of two outer terms is 1, and one of the inner terms is 0.25, what is the other inner term.
在一个比例中，两个外项的积是1，其中一个内项是0.25，则另一个内项是多少．
<gadget id="calculator">1 / 0.25</gadget>
<output>4</output>

<result>4</result>