A cuboid glass fish tank without a cover has a bottom length of 4dm, a width of 25cm, and a height of 20cm. How many square centimeters of glass is required to make such a fish tank? (what do you want?)
一个长方体无盖玻璃鱼缸，它的底长4dm，宽25cm，高20cm，做这样一个鱼缸至少要玻璃多少平方厘米？(求什么？)
<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">40 * 25</gadget>
<output>1_000</output>

<gadget id="calculator">40 * 20</gadget>
<output>800</output>

<gadget id="calculator">25 * 20</gadget>
<output>500</output>

<gadget id="calculator">1_000 + 800 + 500</gadget>
<output>2_300</output>

<gadget id="calculator">2_300 * 2</gadget>
<output>4_600</output>

<gadget id="calculator">4_600 - 1_000</gadget>
<output>3_600</output>

<result>3_600</result>