In the ratio, the two outer terms are the reciprocals of each other, one of the inner terms is 0.8, and the other inner term is what.
在比例里两个外项互为倒数，其中一个内项是0.8，另一个内项是多少．
<gadget id="calculator">1 / 0.8</gadget>
<output>1.25</output>

<result>1.25</result>