A piece of cake is 12cm long, 6cm wide, and 5cm thick. If you cut it with a knife, what is the minimum increase in the surface area in cm**2.
一块蛋糕长12cm，宽6cm，厚5cm，切一刀，表面积最少增加了多少cm**2．
<gadget id="calculator">5 * 6 * 2</gadget>
<output>60</output>

<result>60</result>