The two internal terms of a ratio are reciprocals of each other, one of its external terms is 0.8, and what is the other external term.
一个比例的两个内项互为倒数，它的一个外项是0.8，另一个外项是多少．
<gadget id="calculator">1 / 0.8</gadget>
<output>1.25</output>

<result>1.25</result>