If the ratio of A to B is 0.5, what is the ratio of B to A?
甲数与乙数的比值是0.5，那么乙数与甲数的比值是多少．
<gadget id="calculator">0.5 / 1</gadget>
<output>0.5</output>

<gadget id="calculator">1 / 0.5</gadget>
<output>2</output>

<result>2</result>