It is known that the length of a rectangle is 8 cm, and its width is 5 cm. If its length and width are increased by 2 cm each, how many square centimeters will its area increase?
以知长方形的长是8厘米，宽是5厘米，它的长和宽各增加2厘米，面积增加多少平方厘米．
<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">10 * 7</gadget>
<output>70</output>

<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<gadget id="calculator">70 - 40</gadget>
<output>30</output>

<result>30</result>