To make a cuboid fish tank without a cover, the length is 50cm, the width is 25cm, and the height is 20cm. How many cm**2 glass should be used at least?
做一个没有盖的长方体鱼缸，长50cm，宽25cm，高20cm，至少要用多少cm**2玻璃？
<gadget id="calculator">50 * 25</gadget>
<output>1_250</output>

<gadget id="calculator">50 * 20 * 2</gadget>
<output>2_000</output>

<gadget id="calculator">25 * 20 * 2</gadget>
<output>1_000</output>

<gadget id="calculator">1_250 + 2_000 + 1_000</gadget>
<output>4_250</output>

<result>4_250</result>