The number of A is 30, the number of B is less than the number of A (2/3), what is the number of B?
甲数是30，乙数比甲数少(2/3)，乙数是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">30 * (1/3)</gadget>
<output>10</output>

<result>10</result>