A mailbox is measured from the inside. The bottom is a square with a side length of 3 decimeters and a height of 3.6 decimeters. Calculated on the basis of 0.68 kilograms per liter of gasoline, how many kilograms of gasoline can this kind of mailbox hold?
从里面量一种邮箱，底面是边长3分米的正方形，高3.6分米．按每升汽油重0.68千克计算，这种邮箱可以装汽油多少千克？
<gadget id="calculator">3 * 3 * 3.6</gadget>
<output>32.4</output>

<gadget id="calculator">0.68 * 32.4</gadget>
<output>22.032</output>

<result>22.032</result>