A cuboid water tank, measured from the inside, is 40cm in length and 35cm in width. A steel ball is submerged in the water tank (water overflows at the end), and the water depth is 15cm. After taking out the steel ball, the water depth is 12cm. If steel weighs 7.8 kilograms per cubic decimeter, how many kilograms does the steel ball weigh?
一个长方体水箱，从里面量长是40cm，宽是35cm，水箱中浸没一个钢球(水末溢出)，水深15cm，取出钢球后，水深12cm．如果每立方分米钢重7.8千克，这个钢球重多少千克？
<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<gadget id="calculator">3 / 1_000</gadget>
<output>3/1_000 = around 0.003</output>

<gadget id="calculator">40 * 35 * (3/1_000) * 7.8</gadget>
<output>32.76</output>

<result>32.76</result>