A cubic water tank without a cover has a side length of 6 decimeters. To make 10 such water tanks, how many square meters of iron sheets are needed at least?
一个无盖正方体水箱，棱长6分米，做10个这样的水箱，至少需要铁皮多少平方米？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">6 * 6 * 5 * (1/10)</gadget>
<output>18</output>

<result>18</result>