The number B is half of the number A, the number B is 30, what is the number A
乙数是甲数的一半，乙数是30，甲数是多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / (1/2)</gadget>
<output>60</output>

<result>60</result>