In a ratio, the two internal terms are reciprocals of each other, one of the external terms is 1, and the other external term is 1.
在一个比例中，两个内项互为倒数，其中一个外项为1，另一个外项是多少．
<gadget id="calculator">1 / 1</gadget>
<output>1</output>

<result>1</result>