A cuboid fish tank is 50 cm long, 40 cm wide, and 30 cm high. What is the minimum square centimeter of glass needed to make this fish tank?
一个长方体的鱼缸，长50厘米，宽40厘米，高30厘米．做这个鱼缸至少需要玻璃多少平方厘米？
<gadget id="calculator">50 * 40</gadget>
<output>2_000</output>

<gadget id="calculator">50 * 30</gadget>
<output>1_500</output>

<gadget id="calculator">40 * 30</gadget>
<output>1_200</output>

<gadget id="calculator">1_500 + 1_200</gadget>
<output>2_700</output>

<gadget id="calculator">2_700 * 2</gadget>
<output>5_400</output>

<gadget id="calculator">2_000 + 5_400</gadget>
<output>7_400</output>

<result>7_400</result>