A cylindrical bucket has a bottom diameter of 4 decimeters and a height of 5 decimeters. If the water contained in the bucket just accounts for (4/5) of the volume of the bucket, how many kilograms of water can be filled to fill the bucket? (Weighs 1 kg per cubic decimeter)
一个圆柱形水桶，底面直径是4分米，高是5分米，如果桶内盛的水正好占桶容积的(4/5)，再装入多少千克水就可以把水桶装满？(每立方分米重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 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3.14 * 4 * 5 * (1/5) * 1</gadget>
<output>12.56</output>

<result>12.56</result>