The number of A is 30, which is (1/3) of the number of B. What is the number of B?
甲数是30，是乙数的(1/3)，乙数是多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">30 / (1/3)</gadget>
<output>90</output>

<result>90</result>