The number of A is (2/3) of the number of B. If the number of B is increased by 20, then the number of B is 4 times of the number of A. What is the number of A?
甲数是乙数的(2/3)，如果乙数增加20，则乙数是甲数的4倍，甲数是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">12 * (2/3)</gadget>
<output>8</output>

<result>8</result>