A cuboid fish tank without a cover is 0.4 meters long, 0.25 meters wide, and 0.3 meters deep. At least how many square meters of glass should be used to make this fish tank.
一只无盖的长方体鱼缸，长0.4米，宽0.25米，深0.3米，做这只鱼缸至少要用玻璃多少平方米．
<gadget id="calculator">0.4 * 0.25</gadget>
<output>0.1</output>

<gadget id="calculator">0.4 * 0.3 * 2</gadget>
<output>0.24</output>

<gadget id="calculator">0.25 * 0.3 * 2</gadget>
<output>0.15</output>

<gadget id="calculator">0.1 + 0.24 + 0.15</gadget>
<output>0.49</output>

<result>0.49</result>