What is the area of a rectangle whose width is 5 decimeters and whose length is three times its width?
一个长方形宽是5分米，长是宽的3倍，它的面积是多少平方厘米．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 15 * 100</gadget>
<output>7_500</output>

<result>7_500</result>