The area of a rectangle is 40 square meters, if the length is doubled and the width is doubled, what is its area?
一个长方形的面积是40平方米，如果把长扩大2倍，宽扩大4倍，它的面积是多少．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">40 * 8</gadget>
<output>320</output>

<result>320</result>