The diameter and height of the bottom of a cylindrical bucket are 4 decimeters, and the water level in the bucket is 1.5 decimeters lower than the mouth of the bucket. How many kilograms of water does this bucket have? (1 kg per cubic decimeter of water)
一个圆柱形水桶底面直径和高都是4分米，桶里的水面比桶口低1.5分米，这桶水有多少千克？(每立方分米水重1千克)
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">4 - 1.5</gadget>
<output>2.5</output>

<gadget id="calculator">3.14 * 4 * 2.5 * 1</gadget>
<output>31.4</output>

<result>31.4</result>