If the length of a rectangle is 5 cm and 3 cm, the length and width are each increased by 3 cm, and the area is increased by how many square centimeters.
一个长方形长5厘米，3厘米，长和宽各增加3厘米，面积增加多少平方厘米．
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">3 + 3</gadget>
<output>6</output>

<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">48 - 15</gadget>
<output>33</output>

<result>33</result>