A cylindrical container with a bottom circumference of 12.56 cm is filled with water. When an irregular iron block is placed in the water, the height of the water surface rises from the original 10 cm to 12 cm. What is the volume of this irregular piece of iron?
一个底面周长是12.56厘米的圆柱形容器中装有水，当把一个不规则铁块放在水中时，水面高度由原来的10厘米上升到12厘米．这个不规则铁块的体积是多少？
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">12 - 10</gadget>
<output>2</output>

<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<result>25.12</result>