A packing box for a microwave oven is 0.8m long, 0.5m wide and 0.5m high when measured from the outside. What is its surface area in square meters?
一个微波炉的包装箱，从外面量长0.8m，宽0.5m，高0.5m．它的表面积是多少平方米？
<gadget id="calculator">0.8 * 0.5 * 4</gadget>
<output>1.6</output>

<gadget id="calculator">0.5 * 0.5 * 2</gadget>
<output>0.5</output>

<gadget id="calculator">1.6 + 0.5</gadget>
<output>2.1</output>

<result>2.1</result>