If a rectangle with a length of 3 cm and a width of 2 cm is increased by 1 cm, its area will increase by how many square centimeters
一个长3厘米、宽2厘米的长方形，长增加1厘米，它的面积就增加多少平方厘米
<gadget id="calculator">2 * 1</gadget>
<output>2</output>

<result>2</result>