If a number is reduced by 2 times, then reduced by 2 times, and then reduced by 4 times, the number is 20. What is this number?
一个数缩小2倍，再缩小2倍，再缩小4倍得数是20，这个数是多少．
<gadget id="calculator">20 * 4 * 2 * 2</gadget>
<output>320</output>

<result>320</result>