If the length of a rectangle is 12 meters and 4 times its width, what is its area?
一个长方形的长是12米，是宽的4倍，它的面积是多少．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 * 12</gadget>
<output>36</output>

<result>36</result>