A cuboid fish tank without a cover, the bottom surface is a square with a side length of 3 decimeters and a height of 0.5 meters. How much glass is at least needed to make such a fish tank?
一个无盖的长方体鱼缸，底面是边长为3分米的正方形，高0.5米，做这样一个鱼缸至少要多少玻璃？
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">0.5 * 10</gadget>
<output>5</output>

<gadget id="calculator">3 * 5 * 4</gadget>
<output>60</output>

<gadget id="calculator">9 + 60</gadget>
<output>69</output>

<result>69</result>