A piece of wood 5 decimeters long and whose cross-section is 20 centimeters in diameter is cut vertically in half of equal size by how much the surface area increases
一根长为5分米，横截面是直径为20厘米的圆形木材，沿直径垂直切成同样大的两半，表面积增加了多少
<gadget id="calculator">2 / 100</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">5 * 10 * 20 * (1/50)</gadget>
<output>20</output>

<result>20</result>