Fill in the numbers according to the law: 2.5, 1, 0.4, 0.16, how much.
按规律填数：2.5、1、0.4、0.16、多少．
<gadget id="calculator">2.5 * 0.4 * 0.4 * 2.5 * 0.4 * 0.4 * 2.5 * 0.4 * 0.4</gadget>
<output>0.064</output>

<result>0.064</result>