The two outer terms of a ratio are reciprocals of each other, one inner term is 7, and the other inner term is how much.
一个比例的两个外项互为倒数，一个内项是7，另一个内项是多少．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<result>1/7 = around 0.142857</result>