50 mathematics books are arranged in a cuboid with a length of 18 cm, a width of 13 cm, and a height of 25 cm. What is the average volume of each book?
50本数学书摆成一个长18厘米，宽13厘米，高25厘米的长方体，平均每本书的体积是多少？
<gadget id="calculator">25 / 50</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">18 * 13 * (1/2)</gadget>
<output>117</output>

<result>117</result>