To manufacture a cuboid water tank with a length of 0.8m, a width of 0.5m, and a depth of 2.5m, how much iron sheet is needed?
要制造一个长0.8m，宽0.5m，深2.5m的长方体水箱，需要铁皮多少？
<gadget id="calculator">0.8 * 0.5</gadget>
<output>0.4</output>

<gadget id="calculator">0.8 * 2.5</gadget>
<output>2</output>

<gadget id="calculator">0.5 * 2.5</gadget>
<output>1.25</output>

<gadget id="calculator">0.4 + 2 + 1.25</gadget>
<output>3.65</output>

<gadget id="calculator">3.65 * 2</gadget>
<output>7.3</output>

<result>7.3</result>