How many square meters of iron sheet is needed to make an uncovered granary with a base diameter and a height of 2 meters? If 1 cubic meter holds 500 kilograms of grain, it can hold several tons of grain.
用铁皮做一个底面直径与高都是2米的无盖粮仓，需铁皮多少平方米？如果1立方米装粮500千克，可装几吨粮．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">500 / 1_000</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 1 * 2 * (1/2)</gadget>
<output>3.14</output>

<result>3.14</result>