A rectangular sheet of iron, 6 decimeters long and 5 decimeters wide. After cutting a square with a side length of 1 decimeter from each of the four corners, it can be welded into a cuboid water tank without a cover. What is the volume of this tank in liters?
一块长方形铁皮，长6分米，宽5分米．从四个角上各剪下一个边长1分米的正方形后，可以焊接成一个无盖的长方体水箱．这个水箱的容积是多少升？
<gadget id="calculator">6 - 1 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 - 1 - 1</gadget>
<output>3</output>

<gadget id="calculator">4 * 3 * 1</gadget>
<output>12</output>

<result>12</result>